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How to continue in a nested loop python

Not as elegant as it should be

Photo by Johannes Plenio on Unsplash

We all know that Python is an elegant programming language. But everything has weaknesses. Sometimes Python is not as elegant as it should be.

For example, when we need to break out of nested loops as follows:

for a in list_a:
    for b in list_b:
        if condition[a,b]…

In this article, you will learn to use break and continue statements to alter the flow of a loop.

Video: Python break and continue Statement

What is the use of break and continue in Python?

In Python, break and continue statements can alter the flow of a normal loop.

Loops iterate over a block of code until the test expression is false, but sometimes we wish to terminate the current iteration or even the whole loop without checking test expression.

The break and continue statements are used in these cases.

Python break statement

The break statement terminates the loop containing it. Control of the program flows to the statement immediately after the body of the loop.

If the break statement is inside a nested loop [loop inside another loop], the break statement will terminate the innermost loop.

Syntax of break

break

Flowchart of break

Flowchart of break statement in Python

The working of break statement in for loop and while loop is shown below.

Working of the break statement

Example: Python break

# Use of break statement inside the loop

for val in "string":
    if val == "i":
        break
    print[val]

print["The end"]

Output

s
t
r
The end

In this program, we iterate through the "string" sequence. We check if the letter is i, upon which we break from the loop. Hence, we see in our output that all the letters up till i gets printed. After that, the loop terminates.

Python continue statement

The continue statement is used to skip the rest of the code inside a loop for the current iteration only. Loop does not terminate but continues on with the next iteration.

Syntax of Continue

continue

Flowchart of continue

Flowchart of continue statement in Python

The working of the continue statement in for and while loop is shown below.

How continue statement works in python

Example: Python continue

# Program to show the use of continue statement inside loops

for val in "string":
    if val == "i":
        continue
    print[val]

print["The end"]

Output

s
t
r
n
g
The end

This program is same as the above example except the break statement has been replaced with continue.

We continue with the loop, if the string is i, not executing the rest of the block. Hence, we see in our output that all the letters except i gets printed.

What is the use of break and continue in Python?
Python break statement
- Syntax of break
- Flowchart of break
- Example of break
Python continue statement
- Syntax of Continue
- Flowchart of continue
- Example: Python continue

How do you continue in a nested while loop in Python?

7 Answers.

Break from the inner loop [if there's nothing else after it].

Put the outer loop's body in a function and return from the function..

Raise an exception and catch it at the outer level..

Set a flag, break from the inner loop and test it at an outer level..

Refactor the code so you no longer have to do this..

How do you continue a nested loop?

When continue statement is used in a nested loop, it only skips the current execution of the inner loop. Java continue statement can be used with label to skip the current iteration of the outer loop too.

How do you continue a for loop in Python?

The continue keyword is used to end the current iteration in a for loop [or a while loop], and continues to the next iteration.

Does continue break out of nested for loop?

Break out of nested loops with else and continue You can break all loops with else and continue . The code with explanation is as follows. When the inner loop ends normally without break , continue in the else clause is executed.