Functions in python
Function is some set of statements which executes when it is called and perform a task. We can call them again and again in the program when we require.
OR
Function is a named block which can be reused when we require it.So, we can say that it is reusability of code.It is defined using def keyword
Example of function
def msg():
print("I, am a function")
msg() # calling of function
Output
Calling and called function
Calling Function
The function who calls the other function is called calling function.
Called Function
The function which is being called by the calling function is a called function.
Types of functions
Built-in functions
Functions which are already defined in the python language functions library. print(), input() etc. are the built-in functions
User defined functions
Function which are defined by the user.
User defined functions:
sum() function for adding two numbers
def sum():
n1=10
n2=20
res=n1+n2
print("The sum is ",res)
sum()
Output
sum() function of adding two numbers taking input from user
def sum():
n1=int(input("Enter first number"))
n2=int(input("Enter second number"))
res=n1+n2
print("The sum is ",res)
sum() #calling sum function
Arguments
A value given to the called function from where it is being called.
sum() function with arguments
sum() function for adding two numbers getting two integer arguments from where it is being called
def sum(n1,n2):
res=n1+n2
print("The sum is ",res)
sum(10,20)
Output
Example of getting string argument
def getMessage(msg):
print(msg)
getMessage("Welcome to compuhelp")
Output
Keyword arguments
In keyword arguments the sending and cathing position of the arguments does not matter. In this we pass aguments using key=value syntax.
def item(name,price):
print("The name of item is = "+name)
print("The price of item is = ",price)
item(price=10,name="kitkat")
Output:
The price of item is = 10
Default arguments
Python allows function arguments to have default values. If the function is called without the argument, the argument gets its default value. Default values indicate that the function argument will take that value if no argument value is passed during the function call.
def sum(n1=100,n2=200):
res=n1+n2
print("The sum is",res)
sum(10,20)
Output
Default arguments without passing arguments
def sum(n1=100,n2=200):
res=n1+n2
print("The sum is",res)
sum()