Nested Loops

An inner loop within the repeating block of an outer loop is called Nested Loop.

The Inner Loop will be executed one time for each iteration of the Outer Loop.

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for i in range(2):
  print("Outer: " + str(i))
  for j in range(2):
    print(" Inner: " + str(j))

PYTHON

Outer: 0
 Inner: 0
 Inner: 1
Outer: 1
 Inner: 0
 Inner: 1

Nested Repeating Block

The one highlighted in the blue dotted line is the repeating block of the inner loop.

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for i in range(2):
  print("Outer: " + str(i))
  for j in range(2):
    print(" Inner: " + str(j))
print("END")

PYTHON

In the above example, the below line is the repeating block of the nested loop.

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print(" Inner: " + str(j))

PYTHON

Outer: 0
 Inner: 0
 Inner: 1
Outer: 1
 Inner: 0
 Inner: 1
END

Example - 1: While loop inside a For loop

Example - 2: While loop inside a while loop