Python Loops

Loop is a continuous iteration of a block of code to ensure some condition.

It means a group of instructions will execute multiple number of times.

There are following types of loops

Loop Type	Description
while loop	Repeats a statement or group of statements until a given condition is true. It tests the condition before executing the loop body.
for loop	Execute a sequence of statements multiple times and abbreviates the code that manages the loop variable.
nested loops	You can use one or more loop inside any another while, for or do..while loop.

  x=4
  while x>1:
    print x
    x--

  4
  3
  2

  list = [1, 2, 3]
  for each_num in list
    print each_num

  1
  2
  3

Loop Control Statements:

Loop control statements change execution from its normal sequence

There are following control statements:

Control Statement	Description
break statement	Terminates the loop statement and transfers execution to the statement immediately following the loop.
continue statement	Causes the loop to skip the remainder of its body and immediately retest its condition prior to reiterating.
pass statement	The pass statement in Python is used when a statement is required syntactically but you do not want any command or code to execute.

for letter in 'scanftree.com':  # for loop Example
   print 'Letter :', letter

In the next chapter you are going to learn python