4.2) Importing Modules

To use a module, you have to import it (ie load it):

>>>  import math

You can then use variables or functions defined within the module. For example, the following prints the constants pi and e and then calculates the square root of 3.2 to the power of 2:

>>> print math.pi
>>> print math.e
>>> math.sqrt(3.2**2)

Notice that to use functions or variables from a module, you need to write '.' before the specific function/variable. Don’t forget the dot!

If you only want to use one function from a module, you can import only that specific function and you can avoid writing 'math.' before the function name.

>>>  from math import sqrt   # import the sqrt function from the math module
>>> sqrt(3.2**2)

You can do exactly the same for variables.

Finally, you can use an alias for the module, usually to shorten the name:

>>> import math as ma
>>> print ma.pi