Python Keywords

Just like natural languages, a computer programming language comprises of a set of predefined words which are called keywords. A prescribed rule of usage for each keyword is called a syntax.

Python 3.x has 33 keywords. Since they have a predefined meaning attached, they cannot be used for any other purpose. The list of Python keywords can be obtained using the following help command in Python shell.


The following table list all the keywords in Python.

False def if raise
None del import return
True elif in try
and else is while
as except lambda with
assert finally nonlocal yield
break for not
class from or
continue global pass

Except for the first three (False, None and True), the other keywords are entirely in lowercase.

Use help() command to know more about each individual keyword. The following will display information on theglobal keyword.


Reserved Identifiers

Python built-in classes contains some identifiers that have special meanings. These special identifiers are recognized by the patterns of leading and trailing underscore characters:

Pattern Description Examples
_* _ stores the result of the last evaluation.
>>> 5 * 5 
>>> _
__*__ It represents system-defined identifiers that matches __*__ pattern, also known as dunder names. These can be functions or properties such as __new__(), __init__(), __name__, __main__, etc.
 >>> __name__
__* It represents class's private name pattern. These names are to be used with private member names of the class to avoid name clashes between private attributes of base and derived classes.