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8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	4	<title>Functional Approach</title>
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8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	18	<tr><th colspan="3" align="center">Functional Approach</th></tr>
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8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	21	<a accesskey="p" href="index.html">Prev</a> </td>
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8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	28	<div class="article" title="Functional Approach">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	29	<div class="titlepage">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	30	<div><div><h2 class="title">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	31	<a name="id2496165"></a>Functional Approach</h2></div></div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	32	<hr>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	33	</div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	34	<div class="toc">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	35	<p><b>Table of Contents</b></p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	36	<dl>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	37	<dt><span class="section"><a href="ar01.html#default-arguments">1. Default Arguments</a></span></dt>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	38	<dt><span class="section"><a href="ar01.html#keyword-arguments">2. Keyword Arguments</a></span></dt>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	39	<dt><span class="section"><a href="ar01.html#parameter-packing-and-unpacking">3. Parameter Packing and Unpacking</a></span></dt>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	40	<dt><span class="section"><a href="ar01.html#nested-functions-and-scopes">4. Nested Functions and Scopes</a></span></dt>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	41	<dt><span class="section"><a href="ar01.html#map-reduce-and-filter-functions">5. map, reduce and filter functions</a></span></dt>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	42	<dd><dl><dt><span class="section"><a href="ar01.html#list-comprehensions">5.1. List Comprehensions</a></span></dt></dl></dd>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	43	</dl>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	44	</div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	45	<p id="x_74b"><a name="x_74b"></a>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	46	<span class="emphasis"><em>Functions</em></span> allow us to enclose a set of statements and call the function again and again instead of repeating the group of statements everytime. Functions also allow us to isolate a piece of code from all the other code and provides the convenience of not polluting the global variables.
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	47	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	48	<p id="x_74c"><a name="x_74c"></a>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	49	<span class="emphasis"><em>Function</em></span> in python is defined with the keyword
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	50	<span class="strong"><strong>def</strong></span> followed by the name of the function, in turn followed by a pair of parenthesis which encloses the list of parameters to the function. The definition line ends with a ':'. The definition line is followed by the body of the function intended by one block. The
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	51	<span class="emphasis"><em>Function</em></span> must return a value:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	52	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	53	<pre class="programlisting">def factorial(n):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	54	fact = 1
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	55	for i in range(2, n):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	56	fact *= i
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	57
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	58	return fact
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	59
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	60	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	61	<p id="x_74d"><a name="x_74d"></a>The code snippet above defines a function with the name factorial, takes the number for which the factorial must be computed, computes the factorial and returns the value.</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	62	<p><a name="x_74e"></a>A
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	63	<span class="emphasis"><em>Function</em></span> once defined can be used or called anywhere else in the program. We call a fucntion with its name followed by a pair of parenthesis which encloses the arguments to the function.
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	64	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	65	<p><a name="x_74f"></a>The value that function returns can be assigned to a variable. Let's call the above function and store the factorial in a variable:</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	66	<pre class="programlisting">fact5 = factorial(5)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	67
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	68	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	69	<p><a name="x_750"></a>The value of fact5 will now be 120, which is the factorial of 5. Note that we passed 5 as the argument to the function.</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	70	<p><a name="x_751"></a>It may be necessary to document what the function does, for each of the function to help the person who reads our code to understand it better. In order to do this Python allows the first line of the function body to be a string. This string is called as
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	71	<span class="emphasis"><em>Documentation String</em></span> or
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	72	<span class="emphasis"><em>docstring</em></span>.
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	73	<span class="emphasis"><em>docstrings</em></span> prove to be very handy since there are number of tools which can pull out all the docstrings from Python functions and generate the documentation automatically from it.
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	74	<span class="emphasis"><em>docstrings</em></span> for functions can be written as follows:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	75	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	76	<pre class="programlisting">def factorial(n):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	77	'Returns the factorial for the number n.'
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	78	fact = 1
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	79	for i in range(2, n):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	80	fact *= i
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	81
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	82	return fact
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	83
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	84	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	85	<p><a name="x_752"></a>An important point to note at this point is that, a function can return any Python value or a Python object, which also includes a
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	86	<span class="emphasis"><em>Tuple</em></span>. A
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	87	<span class="emphasis"><em>Tuple</em></span> is just a collection of values and those values themselves can be of any other valid Python datatypes, including
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	88	<span class="emphasis"><em>Lists</em></span>,
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	89	<span class="emphasis"><em>Tuples</em></span>,
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	90	<span class="emphasis"><em>Dictionaries</em></span> among other things. So effectively, if a function can return a tuple, it can return any number of values through a tuple
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	91	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	92	<p><a name="x_753"></a>Let us write a small function to swap two values:</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	93	<pre class="programlisting">def swap(a, b):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	94	return b, a
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	95
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	96	c, d = swap(a, b)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	97
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	98	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	99	<p><a name="x_754"></a>Function scope --------------- The variables used inside the function are confined to the function's scope and doesn't pollute the variables of the same name outside the scope of the function. Also the arguments passed to the function are passed by-value if it is of basic Python data type:</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	100	<pre class="programlisting">def cant_change(n):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	101	n = 10
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	102
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	103	n = 5
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	104	cant_change(n)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	105
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	106	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	107	<p><a name="x_755"></a>Upon running this code, what do you think would have happened to value of n which was assigned 5 before the function call? If you have already tried out that snippet on the interpreter you already know that the value of n is not changed. This is true of any immutable types of Python like
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	108	<span class="emphasis"><em>Numbers</em></span>,
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	109	<span class="emphasis"><em>Strings</em></span> and
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	110	<span class="emphasis"><em>Tuples</em></span>. But when you pass mutable objects like
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	111	<span class="emphasis"><em>Lists</em></span> and
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	112	<span class="emphasis"><em>Dictionaries</em></span> the values are manipulated even outside the function:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	113	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	114	<pre class="programlisting">>>> def can_change(n):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	115	... n[1] = James
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	116	...
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	117
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	118	>>> name = ['Mr.', 'Steve', 'Gosling']
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	119	>>> can_change(name)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	120	>>> name
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	121	['Mr.', 'James', 'Gosling']
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	122
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	123	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	124	<p><a name="x_756"></a>If nothing is returned by the function explicitly, Python takes care to return None when the funnction is called.</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	125	<div class="section" title="1. Default Arguments">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	126	<div class="titlepage"><div><div><h2 class="title" style="clear: both">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	127	<a name="default-arguments"></a>1. Default Arguments</h2></div></div></div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	128	<p><a name="x_757"></a>There may be situations where we need to allow the functions to take the arguments optionally. Python allows us to define function this way by providing a facility called
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	129	<span class="emphasis"><em>Default Arguments</em></span>. For example, we need to write a function that returns a list of fibonacci numbers. Since our function cannot generate an infinite list of fibonacci numbers, we need to specify the number of elements that the fibonacci sequence must contain. Suppose, additionally, we want to the function to return 10 numbers in the sequence if no option is specified we can define the function as follows:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	130	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	131	<pre class="programlisting">def fib(n=10):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	132	fib_list = [0, 1]
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	133	for i in range(n - 2):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	134	next = fib_list[-2] + fib_list[-1]
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	135	fib_list.append(next)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	136	return fib_list
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	137
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	138	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	139	<p><a name="x_758"></a>When we call this function, we can optionally specify the value for the parameter n, during the call as an argument. Calling with no argument and argument with n=5 returns the following fibonacci sequences:</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	140	<pre class="programlisting">fib()
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	141	[0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	142	fib(5)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	143	[0, 1, 1, 2, 3]
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	144
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	145	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	146	</div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	147	<div class="section" title="2. Keyword Arguments">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	148	<div class="titlepage"><div><div><h2 class="title" style="clear: both">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	149	<a name="keyword-arguments"></a>2. Keyword Arguments</h2></div></div></div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	150	<p><a name="x_759"></a>When a function takes a large number of arguments, it may be difficult to remember the order of the parameters in the function definition or it may be necessary to pass values to only certain parameters since others take the default value. In either of these cases, Python provides the facility of passing arguments by specifying the name of the parameter as defined in the function definition. This is known as
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	151	<span class="emphasis"><em>Keyword Arguments</em></span>.
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	152	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	153	<p><a name="x_75a"></a>In a function call,
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	154	<span class="emphasis"><em>Keyword arguments</em></span> can be used for each argument, in the following fashion:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	155	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	156	<pre class="programlisting">argument_name=argument_value
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	157	Also denoted as: keyword=argument
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	158
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	159	def wish(name='World', greetings='Hello'):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	160	print "%s, %s!" % (greetings, name)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	161
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	162	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	163	<p><a name="x_75b"></a>This function can be called in one of the following ways. It is important to note that no restriction is imposed in the order in which
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	164	<span class="emphasis"><em>Keyword arguments</em></span> can be specified. Also note, that we have combined
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	165	<span class="emphasis"><em>Keyword arguments</em></span> with
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	166	<span class="emphasis"><em>Default arguments</em></span> in this example, however it is not necessary:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	167	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	168	<pre class="programlisting">wish(name='Guido', greetings='Hey')
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	169	wish(greetings='Hey', name='Guido')
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	170
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	171	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	172	<p><a name="x_75c"></a>Calling functions by specifying arguments in the order of parameters specified in the function definition is called as
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	173	<span class="emphasis"><em>Positional arguments</em></span>, as opposed to
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	174	<span class="emphasis"><em>Keyword arguments</em></span>. It is possible to use both
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	175	<span class="emphasis"><em>Positional arguments</em></span> and
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	176	<span class="emphasis"><em>Keyword arguments</em></span> in a single function call. But Python doesn't allow us to bungle up both of them. The arguments to the function, in the call, must always start with
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	177	<span class="emphasis"><em>Positional arguments</em></span> which is in turn followed by
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	178	<span class="emphasis"><em>Keyword arguments</em></span>:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	179	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	180	<pre class="programlisting">def my_func(x, y, z, u, v, w):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	181	# initialize variables.
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	182	...
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	183	# do some stuff
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	184	...
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	185	# return the value
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	186
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	187	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	188	<p><a name="x_75d"></a>It is valid to call the above functions in the following ways:</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	189	<pre class="programlisting">my_func(10, 20, 30, u=1.0, v=2.0, w=3.0)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	190	my_func(10, 20, 30, 1.0, 2.0, w=3.0)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	191	my_func(10, 20, z=30, u=1.0, v=2.0, w=3.0)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	192	my_func(x=10, y=20, z=30, u=1.0, v=2.0, w=3.0)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	193
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	194	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	195	<p><a name="x_75e"></a>Following lists some of the invalid calls:</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	196	<pre class="programlisting">my_func(10, 20, z=30, 1.0, 2.0, 3.0)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	197	my_func(x=10, 20, z=30, 1.0, 2.0, 3.0)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	198	my_func(x=10, y=20, z=30, u=1.0, v=2.0, 3.0)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	199
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	200	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	201	</div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	202	<div class="section" title="3. Parameter Packing and Unpacking">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	203	<div class="titlepage"><div><div><h2 class="title" style="clear: both">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	204	<a name="parameter-packing-and-unpacking"></a>3. Parameter Packing and Unpacking</h2></div></div></div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	205	<p><a name="x_75f"></a>The positional arguments passed to a function can be collected in a tuple parameter and keyword arguments can be collected in a dictionary. Since keyword arguments must always be the last set of arguments passed to a function, the keyword dictionary parameter must be the last parameter. The function definition must include a list explicit parameters, followed by tuple paramter collecting parameter, whose name is preceded by a ***, for collecting positional parameters, in turn followed by the dictionary collecting parameter, whose name is preceded by a **** :</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	206	<pre class="programlisting">def print_report(title, args, *name):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	207	"""Structure of args
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	208	(age, email-id)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	209	Structure of name
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	210	{
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	211	'first': First Name
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	212	'middle': Middle Name
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	213	'last': Last Name
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	214	}
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	215	"""
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	216
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	217	print "Title: %s" % (title)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	218	print "Full name: %(first)s %(middle)s %(last)s" % name
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	219	print "Age: %d\nEmail-ID: %s" % args
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	220
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	221	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	222	<p><a name="x_760"></a>The above function can be called as. Note, the order of keyword parameters can be interchanged:</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	223	<pre class="programlisting">>>> print_report('Employee Report', 29, 'johny@example.com', first='Johny',
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	224	last='Charles', middle='Douglas')
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	225	Title: Employee Report
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	226	Full name: Johny Douglas Charles
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	227	Age: 29
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	228	Email-ID: johny@example.com
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	229
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	230	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	231	<p><a name="x_761"></a>The reverse of this can also be achieved by using a very identical syntax while calling the function. A tuple or a dictionary can be passed as arguments in place of a list of Positional arguments or Keyword arguments respectively using *** or **** :</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	232	<pre class="programlisting">def print_report(title, age, email, first, middle, last):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	233	print "Title: %s" % (title)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	234	print "Full name: %s %s %s" % (first, middle, last)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	235	print "Age: %d\nEmail-ID: %s" % (age, email)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	236
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	237	>>> args = (29, 'johny@example.com')
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	238	>>> name = {
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	239	'first': 'Johny',
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	240	'middle': 'Charles',
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	241	'last': 'Douglas'
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	242	}
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	243	>>> print_report('Employee Report', args, *name)
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	244	Title: Employee Report
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	245	Full name: Johny Charles Douglas
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	246	Age: 29
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	247	Email-ID: johny@example.com
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	248
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	249	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	250	</div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	251	<div class="section" title="4. Nested Functions and Scopes">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	252	<div class="titlepage"><div><div><h2 class="title" style="clear: both">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	253	<a name="nested-functions-and-scopes"></a>4. Nested Functions and Scopes</h2></div></div></div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	254	<p><a name="x_762"></a>Python allows nesting one function inside another. This style of programming turns out to be extremely flexible and powerful features when we use
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	255	<span class="emphasis"><em>Python decorators</em></span>. We will not talk about decorators is beyond the scope of this course. If you are interested in knowing more about
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	256	<span class="emphasis"><em>decorator programming</em></span> in Python you are suggested to read:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	257	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	258	<div class="literallayout"><p><br>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	259	<a class="ulink" href="http://avinashv.net/2008/04/python-decorators-syntactic-sugar" target="_top">http://avinashv.net/2008/04/python-decorators-syntactic-sugar</a>/<br>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	260	<a class="ulink" href="http://personalpages.tds.net" target="_top">http://personalpages.tds.net</a>/~kent37/kk/00001.html<br>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	261	</p></div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	262	<p><a name="x_763"></a>However, the following is an example for nested functions in Python:</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	263	<pre class="programlisting">def outer():
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	264	print "Outer..."
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	265	def inner():
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	266	print "Inner..."
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	267	print "Outer..."
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	268	inner()
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	269
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	270	>>> outer()
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	271
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	272	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	273	</div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	274	<div class="section" title="5. map, reduce and filter functions">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	275	<div class="titlepage"><div><div><h2 class="title" style="clear: both">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	276	<a name="map-reduce-and-filter-functions"></a>5. map, reduce and filter functions</h2></div></div></div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	277	<p><a name="x_764"></a>Python provides several built-in functions for convenience. The
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	278	<span class="strong"><strong>map()</strong></span>,
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	279	<span class="strong"><strong>reduce()</strong></span> and
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	280	<span class="strong"><strong>filter()</strong></span> functions prove to be very useful with sequences like
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	281	<span class="emphasis"><em>Lists</em></span>.
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	282	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	283	<p><a name="x_765"></a>The
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	284	<span class="strong"><strong>map</strong></span> (
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	285	<span class="emphasis"><em>function</em></span>,
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	286	<span class="emphasis"><em>sequence</em></span>) function takes two arguments:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	287	<span class="emphasis"><em>function</em></span> and a
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	288	<span class="emphasis"><em>sequence</em></span> argument. The
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	289	<span class="emphasis"><em>function</em></span> argument must be the name of the function which in turn takes a single argument, the individual element of the
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	290	<span class="emphasis"><em>sequence</em></span>. The
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	291	<span class="strong"><strong>map</strong></span> function calls
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	292	<span class="emphasis"><em>function(item)</em></span>, for each item in the sequence and returns a list of values, where each value is the value returned by each call to
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	293	<span class="emphasis"><em>function(item)</em></span>.
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	294	<span class="strong"><strong>map()</strong></span> function allows to pass more than one sequence. In this case, the first argument,
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	295	<span class="emphasis"><em>function</em></span> must take as many arguments as the number of sequences passed. This function is called with each corresponding element in the each of the sequences, or
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	296	<span class="strong"><strong>None</strong></span> if one of the sequence is exhausted:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	297	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	298	<pre class="programlisting">def square(x):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	299	return x*x
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	300
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	301	>>> map(square, [1, 2, 3, 4])
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	302	[1, 4, 9, 16]
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	303
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	304	def mul(x, y):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	305	return x*y
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	306
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	307	>>> map(mul, [1, 2, 3, 4], [6, 7, 8, 9])
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	308
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	309	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	310	<p><a name="x_766"></a>The
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	311	<span class="strong"><strong>filter</strong></span> (
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	312	<span class="emphasis"><em>function</em></span>,
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	313	<span class="emphasis"><em>sequence</em></span>) function takes two arguments, similar to the
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	314	<span class="strong"><strong>map()</strong></span> function. The
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	315	<span class="strong"><strong>filter</strong></span> function calls
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	316	<span class="emphasis"><em>function(item)</em></span>, for each item in the sequence and returns all the elements in the sequence for which
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	317	<span class="emphasis"><em>function(item)</em></span> returned True:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	318	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	319	<pre class="programlisting">def even(x):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	320	if x % 2:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	321	return True
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	322	else:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	323	return False
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	324
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	325	>>> filter(even, range(1, 10))
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	326	[1, 3, 5, 7, 9]
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	327
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	328	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	329	<p><a name="x_767"></a>The
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	330	<span class="strong"><strong>reduce</strong></span> (
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	331	<span class="emphasis"><em>function</em></span>,
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	332	<span class="emphasis"><em>sequence</em></span>) function takes two arguments, similar to
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	333	<span class="strong"><strong>map</strong></span> function, however multiple sequences are not allowed. The
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	334	<span class="strong"><strong>reduce</strong></span> function calls
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	335	<span class="emphasis"><em>function</em></span> with first two consecutive elements in the sequence, obtains the result, calls
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	336	<span class="emphasis"><em>function</em></span> with the result and the subsequent element in the sequence and so on until the end of the list and returns the final result:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	337	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	338	<pre class="programlisting">def mul(x, y):
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	339	return x*y
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	340
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	341	>>> reduce(mul, [1, 2, 3, 4])
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	342	24
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	343
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	344	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	345	<div class="section" title="5.1. List Comprehensions">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	346	<div class="titlepage"><div><div><h3 class="title">
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	347	<a name="list-comprehensions"></a>5.1. List Comprehensions</h3></div></div></div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	348	<p><a name="x_768"></a>List Comprehension is a convenvience utility provided by Python. It is a syntatic sugar to create
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	349	<span class="emphasis"><em>Lists</em></span>. Using
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	350	<span class="emphasis"><em>List Comprehensions</em></span> one can create
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	351	<span class="emphasis"><em>Lists</em></span> from other type of sequential data structures or other
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	352	<span class="emphasis"><em>Lists</em></span> itself. The syntax of
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	353	<span class="emphasis"><em>List Comprehensions</em></span> consists of a square brackets to indicate the result is a
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	354	<span class="emphasis"><em>List</em></span> within which we include at least one
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	355	<span class="strong"><strong>for</strong></span> clause and multiple
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	356	<span class="strong"><strong>if</strong></span> clauses. It will be more clear with an example:
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	357	</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	358	<pre class="programlisting">>>> num = [1, 2, 3]
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	359	>>> sq = [x*x for x in num]
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	360	>>> sq
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	361	[1, 4, 9]
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	362	>>> all_num = [1, 2, 3, 4, 5, 6, 7, 8, 9]
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	363	>>> even = [x for x in all_num if x%2 == 0]
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	364
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	365	</pre>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	366	<p><a name="x_769"></a>The syntax used here is very clear from the way it is written. It can be translated into english as, "for each element x in the list all_num, if remainder of x divided by 2 is 0, add x to the list."</p>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	367	</div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	368	</div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	369	</div>
8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	370	<div class="navfooter">
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8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	375	<a accesskey="p" href="index.html">Prev</a> </td>
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8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	380	<td width="40%" align="left" valign="top">Chapter 1. </td>
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author	amit@thunder
	Mon, 25 Jan 2010 18:56:45 +0530
changeset 0	8083d21c0020
permissions	-rwxr-xr-x