Python looping statement

This tutorial is a Python looping statement. A looping statement is used in the programming language that allows us to repeat a block of the code a number of times.

Python has two types of loops available:

1. While loop
2. For loop

You can also specify else block with looping statement.

While

while loop executes a block of code until the specified condition is true otherwise
terminate the loop.

Syntax

while expression :
    # statement

Example

year = 2001
while year <= 2005 :
    print("Year :",year)
    year+=1

Output:
Year : 2001
Year : 2002
Year : 2003
Year : 2004
Year : 2005

While else

else block executes only when the loop terminates normally not by a break statement.

Syntax

while expression :
    # statement
else:
    # else statement

Example

year = 2001
while year <= 2005 :
    print(year)
    year+=1
else:
    print("year is no longer less than 2006")

Output:
2001
2002
2003
2004
2005
year is no longer less than 2006

For

For loop mostly used for looping over sequences list, tuple, dictionary. for loop executes it stores the first item in loop variable and execute the block code until the sequence is not empty.

Syntax

for variable in sequence :
    # statement

Example

years = [2001,2002,2003,2004,2005]
for year in years :
    print("Year :",year)

Output:
Year : 2001
Year : 2002
Year : 2003
Year : 2004
Year : 2005

For else

for else executes when loop terminates normally not by using break statement.

Syntax

for variable in sequence :
    # statement
else:
    # else statement

Example

years = [2001,2002,2003,2004,2005]
for year in years :
    print("Year :",year)
else:
    print("Years is empty")

Output:
Year : 2001
Year : 2002
Year : 2003
Year : 2004
Year : 2005
Years is empty