Python Modules
Python Modules:-
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.
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 mymodule.py
def greeting(name):?
print("Hello, " + name)
Use a Module:-
Now we can use the module we just created, by using the import statement:
example:-
Import the module named mymodule, and call the greeting function:
import mymodule
mymodule.greeting("Jonathan")
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 mymodule.py
person1 = {? "name": "John",? "age": 36,? "country": "Norway"}
example:-
Import the module named mymodule, and access the person1 dictionary:
import mymodule
a = mymodule.person1["age"]
print(a)
Naming a Module:-
You can name the module file whatever you like, but it must have the file extension .py
Re-naming a Module:-
You can create an alias when you import a module, by using the as keyword:
example:-
Create an alias for mymodule called mx:
import mymodule as mx
a = mx.person1["age"]
print(a)
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)
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)
Note: The dir() function can be used on all modules, also the ones you create yourself.
Import From Module:-
You can choose to import only parts from a module, by using the "from" keyword.
example:-
The module named mymodule has one function and one dictionary:
def greeting(name):?
print("Hello, " + name)
person1 = {? "name": "John",? "age": 36,? "country": "Norway"}
example:-
Import only the person1 dictionary from the module:
from mymodule import person1
print(person1["age"])
Note: When importing using the "from" keyword, do not use the module name when referring to elements in the module. Example: person1["age"], not mymodule.person1["age"]
That's it for now.We will continue in the next article.