Modules are files that contain Python code, which allow us to divide the code into fragments so that it is more organized and easier to reuse.
A module in Python is simply a file with the extension .py
that contains Python code. This code can include definitions of functions, variables, and classes.
Creating a Module
To create a module in Python, we create a file with the extension .py
and write our code in it.
For example, we can create a module called operations.py
with some mathematical operation functions:
# operaciones.py
def suma(a, b):
return a + b
def resta(a, b):
return a - b
def multiplicacion(a, b):
return a * b
def division(a, b):
if b != 0:
return a / b
else:
return "Error: División por cero"
Importing a Module
To use the functions and variables of a module in another Python file, we need to import it. We can import an entire module or import only the functions we need.
Importing an Entire Module
import operaciones
resultado_suma = operaciones.suma(5, 3)
print("Resultado de la suma:", resultado_suma)
resultado_resta = operaciones.resta(10, 4)
print("Resultado de la resta:", resultado_resta)
In this example, we import the entire operations
module and use the suma
and resta
functions that are defined in that module.
Importing Specific Functions from a Module
We can also import specific functions from a module, which can be useful if we only need some functions and do not want to load the entire module.
from operaciones import multiplicacion, division
resultado_multiplicacion = multiplicacion(6, 2)
print("Resultado de la multiplicación:", resultado_multiplicacion)
resultado_division = division(15, 3)
print("Resultado de la división:", resultado_division)
In this case, we import only the multiplicacion
and division
functions from the operations
module.
Alias in Importing
We can also use aliases when importing modules or functions. This allows us to use a shorter or more convenient name in our code.
import operaciones as ops
resultado_suma = ops.suma(5, 3)
print("Resultado de la suma:", resultado_suma)
from operaciones import resta as restar
resultado_resta = restar(10, 4)
print("Resultado de la resta:", resultado_resta)
Python Standard Modules
In addition to creating our own modules, Python includes a standard library with a wide variety of useful modules for various tasks. Some examples are:
math
: Contains common mathematical functions.random
: Allows generating random numbers.datetime
: Provides classes for handling dates and times.os
: Provides functions for interacting with the operating system.
To use these modules, we simply import them in the same way we did with our own operations
module.
Example
In many cases, it is common to have a main file that acts as the entry point to our program. This file can import the necessary modules and execute the main code.
For example, suppose we have a file main.py
that imports and uses the functions from the operations
module.
# main.py
import operaciones as ops
resultado_suma = ops.suma(5, 3)
print("Resultado de la suma:", resultado_suma)
resultado_resta = ops.resta(10, 4)
print("Resultado de la resta:", resultado_resta)
When running main.py
, the functions of the operations
module will be imported and the results of the addition and subtraction will be printed.