Python Essential Reference, Second Edition

Lists and Tuples

Just as strings are sequences of characters, lists and tuples are sequences of arbitrary objects. You create a list as follows:

names = [ "Dave", "Mark", "Ann", "Phil" ] 

Lists are indexed by integers starting with zero. Use the indexing operator to access and modify individual items of the list:

a = names[2]             # Returns the third item of the list, "Ann" 
names[0] = "Jeff"        # Changes the first item to "Jeff" 

The length of a list can be obtained using the len() function:

print len(names)        # prints 4 

To append new items to a list, use the append() method:

names.append("Kate") 

To insert an item into the list, use the insert() method:

names.insert(2, "Sydney") 

You can extract or reassign a portion of a list by using the slicing ...