Functions

A function is a block of organized, reusable code that is used to perform a single, related action. Functions provide better modularity for your application and a high degree of code reusing.

Defining a Function

• In Python a function is defined using the def keyword followed by the function name and parenthesis.

def my_function():
    print("Hello InterviewBit")

• Any input parameters or arguments should be placed within these parentheses. You can also define parameters inside these parentheses.

def my_function(name):
    print("Hello %s" %name)

Functions may return a value to the caller, using the keyword- ‘return’.

def add_numbers(x, y):
    return x + y

Calling Function

Simply write the function’s name followed by (), placing any required arguments within the brackets.

def my_function():
    print("Hello InterviewBit")
def add_numbers(x, y):
    return x + y

# print "Hello InterviewBit"
my_function()

val = add_numbers(2, 3)
print(val)
# print 5

Functions with keyword arguments

• The arguments which have a default value are termed as keyword arguments and required ones are positional arguments.
• These arguments should always be the last ones, i.e. All the required (positional) arguments go first. They are then followed by the optional keyword arguments.
• Arguments without defaults are required otherwise you get a syntax error.

def distance_travelled(t, u = 0, g = 9.81):
    """
    Function distance_travelled calculates the distance travelled by an object
    with initial speed u, in a time interval of t, where acceleration due to gravity is g

    input: t (time taken), u (initial speed) g (acceleration due to gravity)
    output: distance travelled

    Example: 
      >>> distance_travelled(1.0)

          4.905
    """
    d = u*t + 0.5 * g * t**2
    return d

print(distance_travelled(2.0))
print(distance_travelled(2.0, u = 1.0))
print(distance_travelled(2.0, g = 9.7))
print(distance_travelled(g = 9.7, t = 2.0))

Try the following example in the editor below.

You have to complete a function named factorial which will return the factorial of the integer N.
Note: Main code is already implemented, you need to complete the factorial function only.