Python: Essential Reference, Third Edition

Conditionals

The if, else, and elif statements control conditional code execution. The general format of a conditional statement is as follows:

if expression:
    statements
elif expression:
    statements
elif expression:
    statements
...
else:
    statements

If no action is to be taken, you can omit both the else and elif clauses of a conditional. Use the pass statement if no statements exist for a particular clause:

if expression:
    pass            # Do nothing
else:
    statements