How to Use For Loops in Python

09/07/2021

Contents

In this article, you will learn how to use for loops in Python.

Python For Loops

A for loop in Python is used to iterate over a sequence (such as a list, tuple, dictionary, set, or string) and execute a block of code for each item in the sequence.

The syntax for a for loop is:


for variable in sequence:
    # code to be executed

The variable in the for loop is a temporary placeholder for the current item in the sequence. On each iteration of the loop, the next item in the sequence is assigned to the loop variable.

For example:

fruits = ['apple', 'banana', 'cherry']
for fruit in fruits:
    print(fruit)

Output:

apple
banana
cherry
 

The range() function is a built-in function in Python that generates a sequence of numbers. It can be used with the for loop to execute a block of code a specific number of times.

For example:

for i in range(5):
    print(i)

Output:

0
1
2
3
4
 

To loop through a dictionary, you can use the items method, which returns a list of tuples, each containing a key-value pair.

For example:

person = {'name': 'John', 'age': 30, 'city': 'New York'}
for key, value in person.items():
    print(f"{key}: {value}")

Output:

name: John
age: 30
city: New York
 

The enumerate() function can be used to loop over a sequence and keep track of the index of the current item in the sequence.

For example:

fruits = ['apple', 'banana', 'cherry']
for index, fruit in enumerate(fruits):
    print(f"{index}: {fruit}")

Output:

0: apple
1: banana
2: cherry
 

The zip() function can be used to iterate over multiple sequences in parallel.

For example:

fruits = ['apple', 'banana', 'cherry']
colors = ['red', 'yellow', 'red']
for fruit, color in zip(fruits, colors):
    print(f"{fruit} is {color}")

Output:

apple is red
banana is yellow
cherry is red
#Python