# Loops: For loop, while loop

Code can be repeated using a loop. Lines of code can be repeated N times, where N is manually configurable. In practice, it means code will be repeated until a condition is met. This condition is usually (x >=N) but it’s not the only possible condition.

Python has 3 types of loops: for loops, while loops and nested loops.

Related Course:
Complete Python Bootcamp: Go from zero to hero in Python

## For loop

We can iterate a list using a for loop

```#!/usr/bin/python   items = [ "Abby","Brenda","Cindy","Diddy" ]   for item in items: print(item)```

Visualization of for loop:

The for loop can be used to repeat N times too:

```#!/usr/bin/python   for i in range(1,10): print(i)```

## While loop

If you are unsure how many times a code should be repeated, use a while loop.
For example,

```correctNumber = 5 guess = 0   while guess != correctNumber: guess = int(input("Guess the number: "))   if guess != correctNumber: print('False guess')   print('You guessed the correct number')```

## Nested loops

We can combine for loops using nesting. If we want to iterate over an (x,y) field we could use:

```#!/usr/bin/python   for x in range(1,10): for y in range(1,10): print("(" + str(x) + "," + str(y) + ")")```

Nesting is very useful, but it increases complexity the deeper you nest.

## 21 thoughts on “Loops: For loop, while loop”

1. - April 22, 2017

Hi Frank.
There is a little mistake in the “While loop” example. It should be:

` guess = int(input("Guess the number: "))`

Otherwise, the compiler will compare between string and integer, and ‘5’!=5.
Except it – excellent!

1. - April 22, 2017

Thanks Sagi!
I’ve updated the article.