Python For Loops

by

Python For Loops:

 

  • Used to iterate over a sequence (list, tuple, string) or other iterable objects.
  • Iterating over a sequence is called traversal.

 

 

 

For Loop Syntax:

Syntax:

 for element in data:
     Body of for loop

 

Here, element is the variable that takes the value of the item inside the sequence on each iteration. Loop continues unless we reach the last item in the sequence.

 

 

Example:

Find the product of all numbers present in the list.

x=[10,20,30,40,50]
product=1
for element in x:
             product*=element

print(“Product is: {}”.format(product))

Output:

Product is: 12000000

 

 

Range Function[range()]:

Syntax:

range(start, stop, step)

This function does not store all the values in memory, it would be inefficient. So it remembers the start, stop, and step size and generates the next number on the go.

 

Example

for i in range(6):
    print(i)

Output:

0
1
2
3
4
5

 

Example

for i in range(1,20,2):
    print(i)

Output:

1
3
5
7
9
11
13
15
17
19

 

Example

array =['Orange', 'Apple', 'Mango', 'Banana', 'Grapes']

for data in range(len(array)):
    print(array[data])

Output:

Orange
Apple
Mango
Banana
Grapes

 

Example

array =['Orange', 'Apple', 'Mango', 'Banana', 'Grapes']

for data in array:
    print(data)

Output:

Orange
Apple
Mango
Banana
Grapes

 

 

For Loop With Else:

Example

fruits =['Apple', 'Mango', 'Banana']

for elements in fruits:
    print(elements)
else:
    print(‘No Item Left’)

Output:

Apple
Mango
Banana
No Item Left

 

 

Break Statement:

  • Break Statement is used to stop the execution of the loop and come out of it and go to the next statement’s execution directly.
  • It is used in both for loop and while loop.

Syntax

for element in data:

    #code inside for loop
    if condition:
        break
    #code inside for loop

#code outside for loop

 

Example

array = [1,2,3,4]

for data in array:
    if data==3:
        break
    print(data)
else:
    print('Inside the else block')
    
print('Outside The For Loop.')

Output:

1
2
Outside The For Loop.

 

 

Continue Statement:

  • Continue Statement takes us to the next iteration directly.
  • It is also used in both for loop and while loop.

Syntax

for element in data:

    #code inside for loop
    if condition:
        continue
    #code inside for loop

#code outside for loop

 

Example

array = [1,2,3,4]

for data in array:
    if data==3:
       continue
    print(data)
else:
    print('Inside The Else Block.')

Output:

1
2
4
Inside The Else Block.

 

Note: Break statement comes out of else statement also whereas continue statement prints the else part too.

 

 

Nested For Loop:

A loop inside a loop is called the nested loop. For each iteration of the outer loop, the inner loop will be executed once.

 

Syntax

for i in range(r1):     #First For Loop
    for j in range(r2): #Second For Loop Inside First For Loop
        Write Content Here

 

Example:

Pattern Print Using Nested For Loop.

n=8
for i in range(n):
    for j in range(i+1):
        print('*',end=' ')
    print()

Output:

Half-right-triangle-pattern-using-python

 

 

Pass Statement:

  • If for some reason we have a “for loop” with no content, put it in the pass statement to avoid getting an error.
  • It is performing like a null operation.

Example

for x in [1,2,3,4,5,6,7,8]:
    pass

 

Leave a comment