getting_started_with_lists.rst
author Anoop Jacob Thomas<anoop@fossee.in>
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Hello friends and welcome to the tutorial on getting started with
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lists.
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 {{{ Show the slide containing title }}}
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 {{{ Show the slide containing the outline slide }}}
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In this tutorial we will be getting acquainted with a python data
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structure called lists.  We will learn ::
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 * How to create lists
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 * Structure of lists
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 * Access list elements
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 * Append elements to lists
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 * Deleting elements from lists
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List is a compound data type, it can contain data of other data
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types. List is also a sequence data type, all the elements are in
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order and there order has a meaning.
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We will first create an empty list with no elements. On your IPython
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shell type ::
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   empty = [] 
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   type(empty)
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This is an empty list without any elements.
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* Filled lists
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Lets now define a list, nonempty and fill it with some random elements.
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nonempty = ['spam', 'eggs', 100, 1.234]
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Thus the simplest way of creating a list is typing out a sequence 
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of comma-separated values (items) between square brackets. 
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All the list items need not have the same data type.
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As we can see lists can contain different kinds of data. In the
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previous example 'spam' and 'eggs' are strings and 100 and 1.234
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integer and float. Thus we can put elements of heterogenous types in
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lists. Thus list themselves can be one of the element types possible
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in lists. Thus lists can also contain other lists.  Example ::
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      list_in_list=[[4,2,3,4],'and', 1, 2, 3, 4]
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We access list elements using the number of index. The
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index begins from 0. So for list nonempty, nonempty[0] gives the
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first element, nonempty[1] the second element and so on and
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nonempty[3] the last element. ::
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	    nonempty[0] 
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	    nonempty[1] 
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	    nonempty[3]
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We can also access the elememts from the end using negative indices ::
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   nonempty[-1] 
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   nonempty[-2] 
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   nonempty[-4]
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-1 gives the last element which is the 4th element , -2 second to last and -4 gives the fourth
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from last element which is first element.
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We can append elements to the end of a list using append command. ::
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   nonempty.append('onemore') 
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   nonempty
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   nonempty.append(6) 
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   nonempty
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As we can see non empty appends 'onemore' and 6 at the end.
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Using len function we can check the number of elements in the list
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nonempty. In this case it being 6 ::
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	 len(nonempty)
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Just like we can append elements to a list we can also remove them.
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There are two ways of doing it. One is by using index. ::
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      del(nonempty[1])
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deletes the element at index 1, i.e the second element of the
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list, 'eggs'. The other way is removing element by content. Lets say
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one wishes to delete 100 from nonempty list the syntax of the command
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should be :: 
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      a.remove(100)
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but what if their were two 100's. To check that lets do a small
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experiment. ::
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	   a.append('spam') 
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	   a 
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	   a.remove('spam') 
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	   a
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If we check a now we will see that the first occurence 'spam' is removed
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thus remove removes the first occurence of the element in the sequence
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and leaves others untouched.
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{{{Slide for Summary }}}
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In this tutorial we came across a sequence data type called lists. ::
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 * We learned how to create lists.  
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 * Append elements to list.
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 * Delete Element from list.  
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 * And Checking list length.
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{{{ Sponsored by Fossee Slide }}}
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This tutorial was created as a part of FOSSEE project.
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I hope you found this tutorial useful.
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Thank You
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 * Author : Amit Sethi 
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 * First Reviewer : 
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 * Second Reviewer : Nishanth