If the filename is, for instance, mymodule.py, import it as follows:

>>> import mymodule

The standard Python distribution has a math module. After importing it, list the functions and attributes in the module as follows:

>>> import math
>>> dir(math)
['__doc__', '__file__', '__name__', '__package__', 'acos', 'acosh', 'asin', 'asinh', 'atan', 'atan2', 'atanh', 'ceil', 'copysign', 'cos', 'cosh', 'degrees', 'e', 'erf', 'erfc', 'exp', 'expm1', 'fabs', 'factorial', 'floor', 'fmod', 'frexp', 'fsum', 'gamma', 'hypot', 'isinf', 'isnan', 'ldexp', 'lgamma', 'log', 'log10', 'log1p', 'modf', 'pi', 'pow', 'radians', 'sin', 'sinh', 'sqrt', 'tan', 'tanh', 'trunc']

Call the pow() function in the math module:

>>> math.pow(2, 3)
8.0

Notice the dot in the syntax. We can also import a function directly and call it by its short name. Import and call the pow() function as follows:

>>> from math import pow
>>> pow(2, 3)
8.0

Python lets us define aliases for imported modules and functions. This is a good time to introduce the import conventions we are going to use for NumPy and a plotting library we will use a lot:

import numpy as np
import matplotlib.pyplot as plt