











Python Nested Loops
Nested Loop
A nested loop is a loop inside another loop. The “inner loop” will be executed one time for each iteration of the “outer loop”.
If outer loop executes M times and inner loop executes N times , the time complexity of the loop will be (M*N).
A final note on loop nesting is that we can put any type of loop inside of any other type of loop. For example a for loop can be inside a while loop or vice versa


Syntax :
- For/while (Outer Loop):
- For/while( Inner Loop) :
- For/while ( Outer Loop) :
- if and else ( Inner Loop)r
Working :
- The outer loop iterates through the range from 0 to n/len(sequence) and for each item in that sequence.
- It enters the inner loop where it iterates over a range of that item.
- For each iteration of that item, it perform the given operation.
- It only leaves the inner loop when it has completely iterated through a range of that item.
- When it leaves the inner loop, it goes back to the outer loop and the process continues until it has completely iterated over its sequence.


Example :
#python Program
#nested Loop
#for-for nested Loop
for i in range(1,3):
for j in range(1,6): #print the multiplication of 1 and 2
print(i*j,end=‘ ‘)
print(‘ ‘)
#for-while nested loop
j=1
for i in range(1,3):
j=1
while(j<6):
print(i*j, end =‘ ‘)
j=j+1
print(‘ ‘)
#while-while nested loop
i=1
while(i<3):
j=1
while(j<6):
print(i*j,end=‘ ‘)
j=j+1
print(‘ ‘)
i+=1
#while-If nested Loop
i=1
j=1
while(i<3):
if(j<6):
print(i*j, end =‘ ‘)
j=j+1
else:
j=1
i+=1
print(”)
Output:
1 2 3 4 5
2 4 6 8 10
1 2 3 4 5
2 4 6 8 10
1 2 3 4 5
2 4 6 8 10
1 2 3 4 5
2 4 6 8 10
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