For Loop in Python
Updated: May 18, 2020
A loop is a used for iterating over a set of statements again and again. There are three types of loops for, while and do-while in python.
Syntax:
for <variable> in <sequence>:
Here <variable> is a variable that is used for iterating over a <sequence>. All iteration it takes the next value from <sequence> until the last of series is reached.
Example:
Program to print squares of all numbers present in a list
num = [1, 2, 3, 4, 5]
sq = 0
for i in num:
sq = i*i
print(sq)
Output:
1
4
9
16
25
Python for loop example using range () function
Program to print the sum of first 3 natural numbers
sum = 0
for i in range(1, 4):
sum = sum + i
print(sum)
Output:
6
For loop with else block
for i in range(5):
print(i)
else:
print("The loop has completed execution")
Output:
0
1
2
3
4
The loop has completed execution
Nested For loop in Python
When a for loop is present inside another for loop then it is called a nested for loop.
for i in range(3):
for j in range(9, 13):
print(i, ",", j)
Output:
0 , 9
0 , 10
0 , 11
0 , 12
1 , 9
1 , 10
1 , 11
1 , 12
2 , 9
2 , 10
2 , 11
2 , 12