Functions are a block of code that performs the task specified. They either just perform some computation and display the result or returns the result to the main function.
In python, functions are defined with the keyword 'def'.
The syntax for defining a function in python is :
def function_name :
#Block of statements
The keyword def is followed by the name of the function. It is a good practise to name the functions meaningfully representing the task done by it. The function name is followed by a colon (:).
In python, Comments are represented by the symbol #. So here #Block of statements is commented and hence it will not be executed by the compiler.
# is used to comment one line of code.
''' .......''' is used to comment a block of code.
For example,
#this is a commented line of code.
''' this is a block of commented code
Everything in this code will not be looked into by the compiler
This is helpful in commenting many lines of a program
'''
a=5
b=6
print(a+b)
Output :
11
Let us consider a program that prints the sum of two numbers whose sum is calculated and printed inside a function.
def add(a,b):
print(a+b)
add(5,5)
Output:
10
Here you must note that the print statement is indented by a tab space.
The indented code represents the function block.
In the next line, we call the function add() and it executes the block inside the function and prints the result as 10.
This is how functions are implemented in python.
Books to learn the basics of python programming :
1. Python: Programming Basics for Absolute Beginners: Volume 1 (Step-By-Step Python)
2. Learning with Python
Python modules :
In python, functions are defined with the keyword 'def'.
The syntax for defining a function in python is :
def function_name :
#Block of statements
The keyword def is followed by the name of the function. It is a good practise to name the functions meaningfully representing the task done by it. The function name is followed by a colon (:).
In python, Comments are represented by the symbol #. So here #Block of statements is commented and hence it will not be executed by the compiler.
# is used to comment one line of code.
''' .......''' is used to comment a block of code.
For example,
#this is a commented line of code.
''' this is a block of commented code
Everything in this code will not be looked into by the compiler
This is helpful in commenting many lines of a program
'''
a=5
b=6
print(a+b)
Output :
11
Let us consider a program that prints the sum of two numbers whose sum is calculated and printed inside a function.
def add(a,b):
print(a+b)
add(5,5)
Output:
10
Here you must note that the print statement is indented by a tab space.
The indented code represents the function block.
In the next line, we call the function add() and it executes the block inside the function and prints the result as 10.
This is how functions are implemented in python.
Books to learn the basics of python programming :
1. Python: Programming Basics for Absolute Beginners: Volume 1 (Step-By-Step Python)
2. Learning with Python
Python modules :
Let me give a small introduction on working with modules in python.
Modules in python are similar to the header files in c. Python contains many inbuilt modules which can be used for specific purposes.
Simply, module is a file with python code. By importing the module, we import that python code in our program.
Some of the default modules that come with python are date module, time module, etc
Let us see an example implementing the python modules.
Code :
import time
print("The current system time is :")
print(time.asctime(time.localtime(time.time())))
This code accesses the time module and displays the current system time in readable format.
Output:
The current system time is :
Fri Apr 21 23:07:11 2017
This is how we import modules in python and use it in the program.
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