Initial commit getting started with lists.
authoramit
Wed, 22 Sep 2010 10:54:47 +0530
changeset 178 4c7b906e0d21
parent 177 eb5dd4c7c5be
child 179 1d04b6c5ff44
child 194 ca81c0a67c75
Initial commit getting started with lists.
liststart.rst
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+Hello friends and welcome to the tutorial on getting started with
+lists
+
+ {{{ Show the slide containing title }}}
+
+ {{{ Show the slide containing the outline slide }}}
+
+In this tutorial we will be getting acquainted with a python data
+structure called lists .  We will learn :
+How to create lists. 
+Structure of lists .
+Access list elements 
+Append elements to lists 
+Deleting elements from lists
+
+I hope you have ipython running on your system .
+
+
+
+
+List is a compound data type,it can contain data of other data
+types.List is also a sequence data type , all the elements are in
+order and there order has a meaning .
+
+
+
+
+We will first create an empty list with no elements . On your ipython
+shell type ::
+
+   In []: empty = [] In []: type(empty)
+   
+   <type 'list'>
+
+This is an empty list without any elements .
+
+* filled lists
+
+Lets now define a list nonempty and fill it with some random elements.
+
+nonempty = ['spam','eggs', 100, 1.234]
+
+Thus the simplest way of creating a list is typing out a sequence 
+of comma-separated values (items) between square brackets. 
+List items need not all have the same data type.
+
+
+As you can see lists can contain different kinds of data . In the
+previous example 'spam' and 'eggs' are strings and 100 and 1.234
+integer and float . Thus you can put elements of heterogenous types in
+lists.  Thus list themselves can be one of the element types possible
+in lists.  Thus lists can also contain other lists in it .  Example ::
+
+      list_in_list=[[4,2,3,4],'and', 1,2,3,4]
+
+
+We access list elements using the number of index . The
+index begins from 0 . So for list,  nonempty , nonempty[0] gives the
+first element , nonempty[1] the second element and so on and
+nonempty[3] the last element .::
+
+
+	    nonempty[0] 
+	    nonempty[1] 
+	    nonempty[3]
+
+We can also access the elememts from the end using negative indices ::
+   
+   nonempty[-1] 
+   nonempty[-2] 
+   nonempty[-4]
+
+-1 being the last element , -2 second to last and -4 being the first
+ element .
+
+* =append= elements We can append elements to the end of a list using
+append command .::
+
+   nonempty.append('onemore') 
+   nonempty.append(6) 
+   nonempty
+   
+As you can see non empty appends 'onemore' and 6 at the end
+
+Using len function we can check the number of elements in the list
+nonempty .Because we just appended two elements at the end this
+returns us 6.::
+	 
+	 len(nonempty)
+
+Just like you can append elements to a list you can also remove them .
+Their are two ways of doing one is by index no. ::
+
+      del(nonempty[1])
+
+deletes the element at index no.1 , i.e the second element of the
+list, 'eggs'. The other way is removing element by content. Lets say
+one wishes to delete 100 from nonempty list the syntax of the command
+shall be :: a.remove(100)
+
+but what if their were two 100 's . To check that lets do a small
+experiment . ::
+
+	   a.append('spam') 
+	   a 
+	   a.remove('spam') 
+	   a
+
+If we check a now we will see that the first element spam is remove
+thus remove removes only the first instance of the element by sequence
+and leaves others untouched .
+
+
+{{{Slide for Summary }}}
+
+
+In this tutorial we came across a sequence data type called lists 
+We learned how to create lists .  
+Append elements to list .
+Delete Element from list.  
+And Checking list length.
+
+
+{{{ Sponsored by Fossee Slide }}}
+
+This tutorial was created as a part of FOSSEE project.
+
+I hope you found this tutorial useful.
+
+Thank You
+
+
+Author : Amit Sethi 
+First Reviewer :