SEES-hacks: SEESenv/web/html/ch6oop.html@ed38dd9bdb50 (annotated)

0 8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	1	<html>
6 1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	2	<head>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	3	<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	4	<title>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	5	Chapter. oop
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	6	</title>
15 f2383fee6584 Testing amit@thunder parents: 6 diff changeset	7	<link rel="stylesheet" href="/review/support/styles.css" type="text/css" />
f2383fee6584 Testing amit@thunder parents: 6 diff changeset	8	<meta name="generator" content="DocBook XSL Stylesheets V1.74.3" />
f2383fee6584 Testing amit@thunder parents: 6 diff changeset	9	<link rel="shortcut icon" type="image/png" href="/review/support/figs/favicon.png" />
f2383fee6584 Testing amit@thunder parents: 6 diff changeset	10	<script type="text/javascript" src="/review/support/jquery-min.js">
f2383fee6584 Testing amit@thunder parents: 6 diff changeset	11	</script>
f2383fee6584 Testing amit@thunder parents: 6 diff changeset	12	<script type="text/javascript" src="/review/support/form.js">
f2383fee6584 Testing amit@thunder parents: 6 diff changeset	13	</script>
f2383fee6584 Testing amit@thunder parents: 6 diff changeset	14	<script type="text/javascript" src="/review/support/hsbook.js">
f2383fee6584 Testing amit@thunder parents: 6 diff changeset	15	</script>
6 1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	16	</head>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	17	<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
16 2e3d2cadbcb6 Testing amit@thunder parents: 15 diff changeset	18	<div class="chapter" id="ch6oop">
6 1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	19	<div class="titlepage">
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	20	</div>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	21	<div class="toc">
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	22	<p>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	23	<b>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	24	Table of Contents
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	25	</b>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	26	</p>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	27	<dl>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	28	<dt>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	29	<span class="article">
25 ed38dd9bdb50 New build of html solving some of the bugs amit@thunder parents: 24 diff changeset	30	<a href="#id2702442">
24 10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	31	Classes and Objects
6 1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	32	</a>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	33	</span>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	34	</dt>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	35	</dl>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	36	</div>
24 10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	37	<div class="article" title="Classes and Objects">
6 1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	38	<div class="titlepage">
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	39	<div>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	40	<div>
24 10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	41	<h2 class="title">
25 ed38dd9bdb50 New build of html solving some of the bugs amit@thunder parents: 24 diff changeset	42	<a name="id2702442">
24 10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	43	</a>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	44	Classes and Objects
6 1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	45	</h2>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	46	</div>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	47	</div>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	48	<hr />
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	49	</div>
24 10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	50	<p id="ch6oop_1">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	51	In the previous sections we learnt about functions which provide certain level
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	52	of abstraction to our code by holding the code which performs one or more
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	53	specific functionalities. We were able to use this function as many times as we
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	54	wanted. In addition to functions, Python also higher level of abstractions
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	55	through
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	56	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	57	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	58	Classes
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	59	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	60	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	61	and
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	62	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	63	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	64	Objects
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	65	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	66	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	67	.
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	68	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	69	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	70	Objects
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	71	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	72	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	73	can be loosely defined as a
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	74	collection of a set of data items and a set of methods. The data items can be
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	75	any valid Python variable or any Python object. Functions enclosed within a class
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	76	are called as
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	77	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	78	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	79	methods
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	80	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	81	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	82	. If you are thinking if methods are functions why is there
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	83	a distinction between the two? The answer to this will be given as we walk through
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	84	the concepts of
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	85	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	86	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	87	Classes
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	88	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	89	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	90	and
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	91	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	92	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	93	Objects
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	94	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	95	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	96	.
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	97	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	98	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	99	Classes
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	100	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	101	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	102	contain the definition for the
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	103	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	104	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	105	Objects
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	106	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	107	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	108	.
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	109	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	110	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	111	Objects
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	112	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	113	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	114	are instances of
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	115	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	116	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	117	Classes
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	118	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	119	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	120	.
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	121	</p>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	122	<p id="ch6oop_2">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	123	A class is defined using the keyword
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	124	<span class="strong">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	125	<strong>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	126	class
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	127	</strong>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	128	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	129	followed by the class name, in
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	130	turn followed by a semicolon. The statements that a
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	131	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	132	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	133	Class
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	134	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	135	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	136	encloses are written
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	137	in a new block, i.e on the next indentation level:
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	138	</p>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	139	<pre class="programlisting">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	140	class Employee:
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	141	def setName(self, name):
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	142	self.name = name
0 8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	143
24 10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	144	def getName(self):
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	145	return self.name
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	146	</pre>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	147	<p id="ch6oop_3">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	148	In the above example, we defined a class with the name Employee. We also defined
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	149	two methods, setName and getName for this class. It is important to note the
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	150	differences between the normal Python functions and class methods defined above.
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	151	Each method of the class must take the same instance of the class(object) from
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	152	which it was called as the first argument. It is conventionally given the name,
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	153	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	154	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	155	self
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	156	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	157	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	158	. Note that
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	159	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	160	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	161	self
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	162	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	163	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	164	is only a convention. You can use any other name, but
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	165	the first argument to the method will always be the same object of the class
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	166	from which the method was called. The data memebers that belong to the class are
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	167	called as
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	168	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	169	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	170	class attributes
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	171	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	172	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	173	.
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	174	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	175	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	176	Class attributes
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	177	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	178	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	179	are preceded by the object of
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	180	the class and a dot. In the above example,
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	181	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	182	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	183	name
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	184	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	185	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	186	is a class attribute since it
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	187	is preceded by the
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	188	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	189	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	190	self
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	191	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	192	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	193	object.
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	194	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	195	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	196	Class attributes
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	197	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	198	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	199	can be accessed from
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	200	anywhere within the class.
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	201	</p>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	202	<p id="ch6oop_4">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	203	We can create objects of a class outside the class definition by using the same
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	204	syntax we use to call a function with no parameters. We can assign this object
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	205	to a variable:
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	206	</p>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	207	<pre class="programlisting">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	208	emp = Employee()
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	209	</pre>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	210	<p id="ch6oop_5">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	211	In the above example, we create an object named
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	212	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	213	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	214	emp
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	215	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	216	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	217	of the class
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	218	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	219	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	220	Employee
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	221	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	222	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	223	.
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	224	All the attributes and methods of the class can be accessed by the object of the
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	225	class using the standard notation
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	226	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	227	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	228	object.attribute
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	229	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	230	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	231	or
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	232	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	233	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	234	object.method()
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	235	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	236	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	237	.
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	238	Although the first parameter of a class method is the self object, it must not
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	239	be passed as an argument when calling the method. The
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	240	<span class="emphasis">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	241	<em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	242	self
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	243	</em>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	244	</span>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	245	object is implicitly
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	246	passed to the method by the Python interpreter. All other arguments passing rules
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	247	like default arguments, keyword arguments, argument packing and unpacking follow
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	248	the same rules as those for ordinary Python functions:
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	249	</p>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	250	<pre class="programlisting">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	251	>>> emp.setName('John')
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	252	>>> name = emp.getName()
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	253	>>> print name
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	254	John
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	255	>>> print emp.name
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	256	John
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	257	</pre>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	258	<p id="ch6oop_6">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	259	If we at all try to access a class attribute before assigning a value to it, i.e
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	260	before creating it, Python raises the same error as it would raise for the
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	261	accessing undefined variable:
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	262	</p>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	263	<pre class="programlisting">
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	264	>>> emp = Employee()
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	265	>>> emp.name
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	266	Traceback (most recent call last):
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	267	File "class.py", line 10, in <module>
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	268	print e.name
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	269	AttributeError: Employee instance has no attribute 'name'
10074d1357ff Some changes after the horrible problem of writing the same ch9 on all the html pages amit@thunder parents: 16 diff changeset	270	</pre>
6 1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	271	</div>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	272	</div>
1ce9b33fb6ff sorted the problem related to paths amit@thunder parents: 2 diff changeset	273	</body>
0 8083d21c0020 The first commit of all the required files for the review app amit@thunder parents: diff changeset	274	</html>

author	amit@thunder
	Tue, 23 Feb 2010 19:43:04 +0530
changeset 25	ed38dd9bdb50
parent 24	10074d1357ff
child 27	cb14131583c6
permissions	-rw-r--r--