Python – Call function from another file

Given a Python file, we need to call a function in it defined in any other Python file. 
Example:

Suppose there is a file test.py which contains the definition of the function displayText(). 
#test.py>
def displayText(): 
    print( “Geeks 4 Geeks!”)
We need to call the function displayText() in any other Python file such that wherever we call displayText() function displays text present in it. This can be done using Python modules. 

Approach:

1. Create a Python file containing the required functions.
2. Create another Python file and import the previous Python file into it.
3. Call the functions defined in the imported file.

The above approach has been used in the below examples:
Example 1: A Python file test.py is created and it contains the displayText() function.

Python3

# test.py>

# function
def displayText():
    print( "Geeks 4 Geeks !")

Now another Python file is created which calls the displayText() function defined in test.py.

Python3

# importing  all the
# functions defined in test.py
from test import *


# calling functions
displayText()

Output:

Geeks 4 Geeks!

In the above program, all the functions defined in test.py file is imported then a functions is called.
Example 2: A Python file calc.py is created containing addNumbers(), subractNumbers(), multiplyNumbers(), divideNumbers() and modulusNumbers().

Python3

# calc.py>

# functions
def addNumbers(a, b):
    print("Sum is ", a + b)

def subtractNumbers(a, b):
    print("Difference is ", a-b)

def multiplyNumbers(a, b):
    print("Product is ", a * b)

def divideNumbers(a, b):
    print("Division is ", a / b)

def modulusNumbers(a, b):
    print("Remainder is ", a % b)

The functions defined in calc.py is called in another Python file.

Python3

# importing limited functions
# defined in calc.py
from calc import addNumbers, multiplyNumbers


# calling functions
addNumbers(2, 5)
multiplyNumbers(5, 4)

Output:

7
20

In the above program, all the functions defined in calc.py are not imported. 
To import all the functions defined in a Python file:
Syntax:

from file import *

To import only required functions defined in a Python file:
Syntax:

from file import func1, func2, func3

Example 3:
The below Python files test.py and calc.py are created having various function definitions.

Python3

# test.py>

# function defined in test.py
def displayText():
    print("\nGeeks 4 Geeks !")

Python3

# calc.py>

# functions defined in calc.py
def addNumbers(a, b):
    print("Sum is ", a + b)

def subtractNumbers(a, b):
    print("Difference is ", a-b)

def multiplyNumbers(a, b):
    print("Product is ", a * b)

def divideNumbers(a, b):
    print("Division is ", a / b)

def modulusNumbers(a, b):
    print("Remainder is ", a % b)

Both files are imported into an another Python file named file.py.

Python3

# file.py>

# importing all the functions
# defined in calc.py
from calc import *

# importing required functions
# defined in test.py
from test import displayText


# calling functions defined
# in calc.py
addNumbers(25, 6)
subtractNumbers(25, 6)
multiplyNumbers(25, 6)
divideNumbers(25, 6)
modulusNumbers(25, 6)

# calling function defined
# in test.py
displayText()

Output:

Sum is  31
Difference is  19
Product is  150
Division is  4.166666666666667
Remainder is  1

Geeks 4 Geeks!

In the above program, functions defined in test.py and calc.py are called in a different file which is file.py.