**Function**

A function is the simplest callable object in Python.

NOTE: For Indentation either use TAB space or 4 space characters, never both.

def tax(bill):

“””Adds 25% tax to a restaurant bill.”””

bill *= 1.25

print “With tax: %f” % bill

return bill

def tip(bill):

“””Adds 35% tip to a restaurant bill.”””

bill *= 1.35

print “With tip: %f” % bill

return bill

meal_cost = 100

meal_with_tax = tax(meal_cost)

meal_with_tip = tip(meal_with_tax)

**Function Syntax**

def spam(): **/*Header*/**

“”” This is spam function””” **/* Comment*/**

print “Spaceship!” ** /*body*/**

spam()

**Call and Response**

def square(n):

“””Returns the square of a number.”””

squared = n**2

print “%d squared is %d.” % (n, squared)

return squared

square(5)

**Parameters and Arguments**

A function can require as many parameters as you’d like, but when called the function, it should generally pass in a matching number of arguments.

def power(base, exponent): # Add your parameters here!

result = base**exponent

print “%d to the power of %d is %d.” % (base, exponent, result)

power(20, 6) # Add your arguments here!

**Functions Calling Functions**

A function can call another function.

def n_plus_one(n):

return n + 1

def couple_add(n):

return n_plus_one(n) + 2

**Importing Module**

A module is a file that contains definitions, including variables and functions, that we can use once it is imported.

import math

print math.sqrt(25)

**math** includes a number of useful variables and functions, and sqrt() is one of those functions. In order to access math, all you need is the import keyword. When you simply import a module this way, it’s called a **generic import**.

It’s possible to import only specific variables or functions from a given module. Pulling in just a single function from a module is called a **function import.**

# Import *just* the sqrt function from math

from math import sqrt

if we want all the variables and functions in a module but don’t want to have to constantly type math then we can use

# Import *everything* from the math module

from math import *

**Built-in Functions**

**max()**

The max() function takes any number of arguments and returns the largest one.

>> maximum = max(10,35,64)

>> print maximum

**min()**

min() function returns the smallest of a given series of arguments.

>> minimum = (10,35,64)

>> print minimum

**abs()
**

The abs() function returns the absolute value of the number it takes as an argument, it gives the number’s distance from 0 on an imagined number line.

>> absolute = abs(-42)

>> print absolute

**type()
**

The type() function returns the type of the data it receives as an argument.

>> print type(42)

>> print type(4.2)

>> print type(‘spam’)

Now let us see the code which returns biggest, smallest and absolute values.

def biggest_number(*args):

print max(args)

return max(args)

def smallest_number(*args):

print min(args)

return min(args)

def distance_from_zero(arg):

print abs(arg)

return abs(arg)

biggest_number(-105, -53, 51, 100)

smallest_number(-106, -55, 54, 105)

distance_from_zero(-104)

These are some of the functions and built-in functions in python.