Book Image

NumPy: Beginner's Guide

By : Ivan Idris
Book Image

NumPy: Beginner's Guide

By: Ivan Idris

Overview of this book

Table of Contents (21 chapters)
NumPy Beginner's Guide Third Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
NumPy Functions' References
Index

Time for action – importing modules


Importing modules can be done in the following manner:

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

    >>> import mymodule
    
  2. 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']
    
  3. 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
    
  4. 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

What just happened?

We learned about modules, importing modules, importing functions, calling functions in modules, and the import conventions of this book. This concludes the Python refresher.