Standard library modules

Commonly used standard library modules that must be imported are as follows:

• datetime: The datetime module has date and time information, and can convert date data formats
• math: The math module is for higher level math functions, such as getting a value for Pi or squaring a number
• string: The string module is used for string manipulations
• csv: The csv module is used for creating, accessing, and editing text spreadsheets.

Check out https://docs.python.org/2/library/ for a complete list of the built-in modules.