For loop of Python

The for loop in python has the ability to iterate over the items of any sequence, such as a list or a string.

The syntax of the loop look is:

for iterating_var in sequence:

            statements(s)

if a sequence contains an expression list, it is evaluated first. Then, the first item in the sequence is assigned to the iterating variable iterating_var. Next, the statements block is executed. Each item in the list is assigned to iterating_var, and the statements(s) block is executed until the entire sequence is exhausted.

Note: in python, all the statements indented by the same number of character spaces after a programming construct are considered to be part of a single block of code. Python uses indentation as its method of grouping statements.

Example:

#!/usr/bin/python

for letter in ‘python’ :            #First Example

            print ‘Curre t Letter : ’, letter

fruits = [‘banana’, ‘apple’, ‘mango’]

for fruit in fruits:        #Second Example

            print  ‘Current fruit :’, fruit

print  “Good bye!”

This will produce following result:

Current Letter  :  P

Current Letter  :  y

Current Letter  :  t

Current Letter  :  h

Current Letter  :  o

Current Letter  :  n

Current fruit    : banana

Current fruit   : apple

Current fruit  :  mango

Good bye!

Iterating by sequence index:

An alternative way of iterating through each item is by index offset into the sequence itself:

Example:

#!/usr/bin/python

fruits = [‘banana’, ‘apple’, ‘mango’]

for index in range (len(fruits)):

              print  ‘Current fruit  :’,  fruits[index]

print “Good bye!”

This will produce following result:

Current fruit  : banana

Current fruit  : apple

Current fruit  : mango

Good bye!