In this article, we will discuss about Python Modules and also learn about how to create and import custom python modules and renaming python module.
What are Python Modules?
In python, a module is file which contains a set of statements and definitions of python programming language. A Python module is similar to a code library where we can define variables, functions and classes. Simply, we can say that module is a code file in python saved with .py extension such as a file naming test.py is a module and the module name is test. With python modules we can organize the code flexibly and in logical manner. Modules allows us to reuse codes and manage a large program into small organized files.
Create a Python module
In order to create a module in python programming language, we just have to save the code in a file with .py file extension.
Let's create a new Python file named with solutions.py and add the following :
# solutions.py># functions
def add(x, y):
print("Sum of two number is ", x + y)
def subtract(x, y):
print("Difference between two number is ", x-y)
def multiply(x, y):
print("Product of two number is ", x * y)
def divide(x, y):
print("Division by two number is ", x / y)
In above example, we have defined add(), subtract(), multiply() and divide() functions inside a module named with solutions.py
Import Python Module
In python, to use the functionality of a module, we have to load/import the module in python code. We can import a python module in following ways;
The import statement
With the import statement we can import the functions, variables and classes that are defined in a module into the another module. In a single import statement we can import multiple numbers of modules but we can load a module only once.
Syntax:
import moduleWhen we enter the import statement, the interpreter imports the module into the other module, if that module is in the search path.
# importing module solutions.pyimport solutions
print(solutions.add(5, 3))
Output
8
The from...import statement
In python, we can import specific attributes from a module instead of importing the module as whole into the namespace. It is possible with the from...import statement.
Syntax:
from module_name import name1, name2, name3...
Now let's illustrate from...import statement with following example:
# importing limited functions# defined in solutions.py
from solutions import add, subtract, multiply
# calling functions
add(2, 10)
subtract(5, 4)
multiply(5, 8)
Output
121
40
Import all names (from...import* statement)
Python allows us to import all names (definitions) to a current namespace from a module by using the * symbol with the from...import statement.
Syntax:
from module_name import*
Now let's illustrate from...import* statement with following example:
# defined in solutions.pyfrom solutions import*
# calling functions
# in solutions.py
add(15, 4)
subtract(5, 1)
multiply(7, 6)
divide(100, 4)
Output
The sum of two number is 19Difference between two number is 4
Product of two number is 42
Division by two number is 25
Renaming Python Module
In python, we can rename a module with a specific name while importing it by using the as keyword.
Syntax:
import module_name as specific_name
Now let's illustrate renaming python module with following example:
# defined in solutions.pyimport solutions as soln;
x = int(input("Enter value for x:"));
y = int(input("Enter value for y:"));
print("Sum of total number is = ",soln.add(x,y))
Output
Enter value for x:5Enter value for y:15
Sum of total number is = 20
Locating Python Modules
In python, when we import a module the python interpreter looks in various locations. Firstly, the interpreter checks the built-in module and if it can't find then it checks the directory's list which are defined in the sys.path.
The python interpreter search in the following order;
• First, it checks the current directory.
• Then it checks other directories in PYTHONPATH.
• And if fails, it checks the installation-dependent directories.
# importing sys moduleimport sys
# importing sys.path
print(sys.path)
Output
['','C:\\Python33\\Lib\\idlelib','C:\\Windows\\system32\\python34.zip','C:\\Python33\\DLLs','C:\\Python33\\lib',
'C:\\Python33','C:\\Python33\\lib\\site-packages']
Reloading Python Modules
As we above learnt that we can load a module only once into the source file of python.
But if you want to reload a module that python provide us the reload() function.
Syntax:
reload(module)
The dir() built-in function
To find out the names that are defined by a module, we use the dir() built-in function. It returns a sorted list of variables, classes, functions, sub-modules that are defined in a particular module.
# Import built-in module randomimport random
print(dir(random))
Output
['BPF', 'LOG4', 'NV_MAGICCONST', 'RECIP_BPF', 'Random', 'SG_MAGICCONST', 'SystemRandom', 'TWOPI', '_Sequence', '_Set', '__all__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', '_accumulate', '_acos', '_bisect', '_ceil', '_cos', '_e', '_exp', '_inst', '_log', '_os', '_pi', '_random', '_repeat', '_sha512', '_sin', '_sqrt', '_test', '_test_generator', '_urandom', '_warn', 'betavariate', 'choice', 'choices', 'expovariate', 'gammavariate', 'gauss', 'getrandbits', 'getstate', 'lognormvariate', 'normalvariate', 'paretovariate', 'randint', 'random', 'randrange', 'sample', 'seed', 'setstate', 'shuffle', 'triangular', 'uniform', 'vonmisesvariate', 'weibullvariate']
Simply, we can say that by using the dir() function we can find out all names that are defined in the present namespace.
Conclusion
From above we have learnt about about how to create and import custom python modules and renaming python module. In python, a module is file which contains a set of statements and definitions of python programming language. To create a module in python programming language, we just have to save the code in a file with .py file extension. In python, to use the functionality of a module, we have to load/import the module in python code.