Secret Recipes of the Python Ninja

How to do it...

1. The most common use of an interator is to loop through a sequence, printing out each element:

 

• • In the preceding example, we have simply iterated through a variety of sequence containers, specifically a list (line 1), a tuple (line 2), dictionary keys (line 3), characters in a string (line 4), and lines in a file (line 5).
  • While a dictionary is not a sequence type but a mapping type, it does support iteration, as it has an iter() call that is only applicable to a dictionary's keys.

2. When a for statement is used, it calls the built-in iter() function on the container. The iter() function returns an iterator object that ...