getting-started-with-lists/getting_started_with_lists.rst
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parent 208 0f78508a4478
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+++ b/getting-started-with-lists/getting_started_with_lists.rst	Wed Oct 13 17:10:38 2010 +0530
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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
+
+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 ::
+
+   empty = [] 
+   type(empty)
+   
+
+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. 
+All the list items need not have the same data type.
+
+
+
+As we 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 we 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.  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 gives the last element which is the 4th element , -2 second to last and -4 gives the fourth
+from last element which is first element.
+
+We can append elements to the end of a list using append command. ::
+
+   nonempty.append('onemore') 
+   nonempty
+   nonempty.append(6) 
+   nonempty
+   
+As we 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. In this case it being 6 ::
+	 
+	 len(nonempty)
+
+
+
+Just like we can append elements to a list we can also remove them.
+There are two ways of doing it. One is by using index. ::
+
+      del(nonempty[1])
+
+
+
+deletes the element at index 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
+should 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 occurence 'spam' is removed
+thus remove removes the first occurence of the element in the 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.  
+ * How to access 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 : 
+ * Second Reviewer : Nishanth