What are modules in python full explained with examples | Python tutorial lesson - 46

 

What is a Module?

Consider a module to be the same as a code library. A file containing a set of functions you want to include in your application. module is created on a separate page and then we can import that page in our file. The name of a Python file is the name of the model.

You can name the module file whatever you like, but it must have the file extension .py

Create a Module

To create a module just save the code you want in a file with the file extension .py:

Example

Save this code in a file named mod.py

def myf1(name):
  print("Hello, My name is : " + name)

Use a Module

Now we can use the module we just created, by using the import statement in new python file:

Example

Import the module named mod, and call the myf1 function:

import mod
mod.myf1("Manoj")

Output:

Hello, My name is Manoj

Note: When using a function from a module, use the syntax: module_name.function_name.

Variables in Module

The module can contain functions, as already described, but also variables of all types (arrays, dictionaries, objects etc):

Example

Save this code in the file mod.py

dic = {
  "name": "Manoj",
  "age": 40,
  "country": "India"
}

Example

Import the module named mob, and access the the dictionary:

import mod

a = mod.dic["age"]
print(a)

Output:

40

Re-naming a Module (alias)

You can create an alias when you import a module, by using the as keyword:

Example

Create an alias for mod called m:

import mod as m

a = m.the["age"]
print(a)

Output:

40

Import From Module

You can choose to import only parts from a module, by using the from keyword.

Example

The module named mod has one function and one dictionary:

def myf1(name):
  print("Hello, My name is: " + name)

dic = {
  "name": "Manoj",
  "age": 40,
  "country": "India"
}

Example

Import only the dic dictionary from the module:

from mod import dic

print (dic["age"])

Output:

40

Note: When importing using the from keyword, do not use the module name when referring to elements inf the module. Example: dic["age"], not mod.dic["age"]

Example

The module named mod has all function and all dictionary:

def myf1(name):
  print("Hello, My name is: " + name)

dic = {
  "name": "Manoj",
  "age": 40,
  "country": "India"
}

def myf2(a,b):
  print(a+b)

Example

Import the all dictionary and functions from the mod module:

from mod import *

print (dic["age"])

mod.myf1("Manoj")

mod.myf2(10,20)

Output:

40

Hello, My name is Manoj

30

Built-in Modules

There are several built-in modules in Python, which you can import whenever you like.

Example

Import and use the platform module:

import platform

x = platform.system()
print(x)

Output:

Windows

Using the dir() Function

There is a built-in function to list all the function names (or variable names) in a module. The dir() function:

Example

List all the defined names belonging to the platform module:

import platform

x = dir(platform)
print(x)

Output:

'WIN32_CLIENT_RELEASES', 'WIN32_SERVER_RELEASES', '__builtins__', '__cached__', '__copyright__', '__doc__', '__file__', '__loader__', '__name__', '__package __', '__spec__', '__version__', '_default_architecture', '_dist_try_harder', '_follow_symlinks', '_ironpython26_sys_version_parser', '_ironpython_sys_version_parser', '_java_getprop', '_libc_search', '_linux_distribution', '_lsb_release_version', '_mac_ver_xml', '_node', '_norm_version', '_perse_release_file', '_platform', '_platform_cache', '_pypy_sys_version_parser', '_release_filename', '_release_version', '_supported_dists', '_sys_version', '_sys_version_cache', '_sys_version_parser', '_syscmd_file', '_syscmd_uname', '_syscmd_ver', '_uname_cache', '_ver_output', 'architecture', 'collections', 'dist', 'java_ver', 'libc_ver', 'linux_distribution', 'mac_ver', 'machine', 'node', 'os', 'platform', 'popen', 'processor', 'python_branch', 'python_build', 'python_compiler', 'python_implementation', 'python_revision', 'python_version', 'python_version_tuple', 're', 'release', 'subprocess', 'sys', 'system', 'system_aliases', 'uname', 'uname_result', 'version', 'warnings', 'win32_ver']

Note: The dir() function can be used on all modules, also the ones you create yourself.

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