Functions are named block of code that can be used anywhere any number of times in the program. It allow us to re-use the code instead of writing the code again and again.
To define a function, we write:
Syntax:
def function_name:
statement_1
statement_2
Here is an example:
def say_hello():
print("Hello")
Now, to call this function, we can simply write:
say_hello()
Here are some examples on functions:
Example 1
Creating a simple function.
def say_hello():
print("Hello")
say_hello()
Example 2
Passing value to function.
def square(x):
print("Square of %d is %d" % (x, x*x))
square(5)
Example 3
Returning value from function.
def find_big(x,y):
return x if x>y else y
big = find_big(7,5)
print("The bigger number is " , big)
Example 4
Loop inside function.
def factorial(x):
fact = 1
for i in range(1,x+1):
fact *= i
return fact
x = 5
print("Factorial of %d is %d" % (x, factorial(x)))
Example 5
Passing a function into another function call.
def square(x):
return x*x
def find_big(x,y):
return x if x>y else y
a,b = 7,5
print("The square of bigger number between %d and %d is %d" % (a,b,square(find_big(a,b))))
Example 6
Recursive function.
def factorial(x):
if x>1:
return x * factorial(x-1)
else:
return 1
x = 5
print("Factorial of %d is %d" % (x, factorial(x)))
Example 7
Returning multiple values from function.
def numbers():
return (4,5)
x,y = numbers()
print("Sum of %d and %d is %d" % (x,y, x+y))