diff -r fcb9936eb009 -r 71697b10f4ae manipulating-lists/script.rst --- a/manipulating-lists/script.rst Mon Nov 15 16:07:00 2010 +0530 +++ b/manipulating-lists/script.rst Tue Nov 16 23:26:42 2010 +0530 @@ -11,8 +11,9 @@ .. 3. .. Author : Madhu - Internal Reviewer : + Internal Reviewer : Punch External Reviewer : + Language Reviewer : Bhanukiran Checklist OK? : [2010-10-05] Script @@ -24,10 +25,10 @@ {{{ Show the slide containing the outline }}} -We have already learnt a lot about Lists in Python. In this tutorial, -we will learn more about advanced features of Lists in Python. We will -see how to concatenate two lists, details of slicing and striding of -lists, methods to sort and reverse lists. +We have already learnt about Lists in Python. In this tutorial, +we will learn about more advanced features of Lists in Python like how +to concatenate two lists, details of slicing and striding of lists, +methods to sort and reverse lists. {{{ Shift to terminal and start ipython }}} @@ -49,16 +50,16 @@ primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29] -To obtain the all the primes between 10 and 20 from the above list of +To obtain all the primes between 10 and 20 from the above list of primes we say:: primes[4:8] This gives us all the elements in the list starting from the element -with the index 4 which is 11 in our list upto the element with index 8 +with the index 4, which is 11 in our list, upto the element with index 8 in the list but not including the eigth element. So we obtain a slice starting from 11 upto 19th. It is a very important to remember that -when ever we specify a range of elements in Python the start index is +whenever we specify a range of elements in Python the start index is included and end index is not included. So in the above case, 11 which was the element with the index 4 was included but 23 which was the element with index 8 was excluded. @@ -129,7 +130,7 @@ gives us all the multiples of 3 from the list, since every third element in it, starting from 0, is divisible by 3. -The other basic operation that we can perform on list is concatenation +The other basic operation that we can perform on lists is concatenation of two or more lists. We can combine two lists by using the "plus" operator. Say we have @@ -160,7 +161,7 @@ a [1, 5, 6, 7, 7, 10] -Since the sort method sorts the list inplace the original list we had +As the sort method sorts the elements of a list, the original list we had is overwritten or replaced. We have no way to obtain the original list back. One way to avoid this is to keep a copy of the original list in another variable and run the sort method on the list. However Python @@ -174,8 +175,7 @@ sa = sorted(a) -Similarly to perform certain operations on the list we would like to -reverse the list. Python provides reverse method which again reverses +Python also provides the reverse method which reverses the list inplace:: a = [1, 2, 3, 4, 5]