# 4.1 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.