For Loop in Python

For Loop in Python

Python provide three ways for executing the loop , For loop is one of them. For loops are used for sequential traversal. If we want to iterate over natural numbers , we can make a list of the number or we can use Range keyword.

for-loop in python

For Loop in Python

A for loop is used to iterate over a sequence (such as a list, tuple, string, or range) and execute a block of code for each item in the sequence. 

Syntax :

  • for iterator_variable in sequence:
    • #body of the loop 
  • Example:
    • for i in list/string:
      •  body of the loop.
implementation of for loop in python

Code :

Run
#python program to illustrate for loop 
list=[1,2,3,4]
for i in list: # i will acquire the value's in the list one by one 
    print(i,end=' ') 
print('')
x={'A':1,'B':2}
for i in x.keys(): # i will have the values of key of the dictionary
    print(x[i] , end=' ') 
print('')
# if we want to iterate over natural number from 0 to 5 
n=5
for i in range(n+1): # loop will run 6 times for 0 1 2 3 4 5 
    print(i,end=' ')  
print('')
#for loop from 2 to 5 
n=5 
for i in range(2,n+1):
    print(i,end=' ') 
print('')
#loop with incremenation=2 
n=12
for i in range(2,n,2):  #all the even numbers from 2 to 11
    print(i, end=' ')  
print('')
#loop from n to 0 
n=5 
for i in range(n,-1,-1): # loop from n to -1 (excluding) with rate of -1 (we can change the rate to -2 or -3)
    print(i,end=' ') 
print('')
#nested for loop 
for i in range(2):
    for j in range(2):  # loop will rum 2*2 = 4 times 
        print(i , end=' ')
    print('')
Output:
1 2 3 4
1 2
0 1 2 3 4 5
2 3 4 5
2 4 6 8 10
5 4 3 2 1 0
0 0
1 1

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