If Statements

Perhaps the most well-known statement type is the if statement. For example:

>>> if x < 0:
...      x = 0
...      print 'Negative changed to zero'
... elif x == 0:
...      print 'Zero'
... elif x == 1:
...      print 'Single'
... else:
...      print 'More'
...

There can be zero or more elif parts, and the else part is optional. The keyword `elif' is short for `else if', and is useful to avoid excessive indentation. An if...elif...elif... sequence is a substitute for the switch or case statements found in other languages.