One of my first tasks as a new QA engineer / Python dev back in the day was to figure out how do you repeat code in Python, how to iterate from 0 to 10 in Python or how do I repeat code in Python forever. Let’s look into possible solutions in this post.

How Do You Repeat Code In Python?

There are a few ways to repeat code in Python, but for loops are a very common way to repeat code in Python, especially when you need to iterate over a sequence of items (such as a list, tuple, or string).

They are easy to use and can be more efficient than using a while loop, especially when you know exactly how many times you need to repeat the code.

To repeat a block of code a specific number of times use:

# Repeat 5 times
for index in range(5):
    print(f'iteration index: {index}')

Output:

iteration index: 0
iteration index: 1
iteration index: 2
iteration index: 3
iteration index: 4

To iterate over a sequence (such as a list, tuple, or string) use:

# Iterate over a list
repeat_items = ['apple', 'banana', 'cherry']

for item in repeat_items:
    print(f'item: {item}')

Output:

item: apple
item: banana
item: cherry

🚨 This is a very simple answer to a How Do You Repeat Code In Python? question. I’ll give you a way more detailed answer based on real Python project examples I’ve gathered over the years in the following sections of this post.

How To Iterate From 0 To 10 In Python?

To iterate from 0 to 10 in Python, you can use a for loop like this:

for index in range(11):
    print(f'iteration index: {index}')

This will print the numbers 0 through 10.

iteration index: 0
iteration index: 1
iteration index: 2
iteration index: 3
iteration index: 4
iteration index: 5
iteration index: 6
iteration index: 7
iteration index: 8
iteration index: 9
iteration index: 10

The range function generates a sequence of numbers from 0 up to, but not including, the number specified as its argument (in this case, 11).

How Do You Add Numbers From 1 To 10 In Python?

To add the numbers from 1 to 10 in Python, you can use a for loop like this:

sum = 0

for number in range(1, 11):
    print(f'number: {number}')
    sum += number

print(f'\nsum: {sum}')

This will add the numbers 1 through 10 and print the result, 55:

number: 1
number: 2
number: 3
number: 4
number: 5
number: 6
number: 7
number: 8
number: 9
number: 10

sum: 55

You must have noticed by now that range() function in Python is a built-in function that returns a sequence of numbers, starting from 0 by default, and increments by 1 (also by default), and stops before a specified number.

Here is the basic syntax for using range():

range(stop)

This will create a sequence of numbers from 0 to stop - 1.

You can also specify a start value and an increment value.

range(start, stop[, step])

And here’s a code example:

sum = 0

# start = 1, stop = 11, step = 2
for number in range(1, 11, 2):
    print(f'number: {number}')
    sum += number

print(f'\nsum: {sum}')

This will output:

number: 1
number: 3
number: 5
number: 7
number: 9

sum: 25

How To Get Value And Index In For Loop In Python?

To get the value and index of an element in a sequence during a for loop in Python, you can use the enumerate() function.

enumerate() takes an iterable object, such as a list, and returns an iterator that produces tuples containing the index and value of each element of the object.

Here is an example of using enumerate() in a for loop:

fruits = ['apple', 'banana', 'mango']

for fruit_index, fruit in enumerate(fruits):
    print(f'fruit_index: {fruit_index}, fruit: {fruit}')

This will output:

fruit_index: 0, fruit: apple
fruit_index: 1, fruit: banana
fruit_index: 2, fruit: mango

You can also specify a start index for the enumeration by passing a second argument to enumerate().

For example:

fruits = ['apple', 'banana', 'mango']

for fruit_index, fruit in enumerate(fruits, start=1):
    print(f'fruit_index: {fruit_index}, fruit: {fruit}')

This will output:

fruit_index: 1, fruit: apple
fruit_index: 2, fruit: banana
fruit_index: 3, fruit: mango

How Do I Print A Value And Key From A For Loop?

To print a value and key from a for loop, you can use the items() method of a dictionary.

The items() method returns an iterator that produces tuples containing the key-value pairs of the dictionary.

Here is an example of using the items() method in a for loop:

fruits = {
    'apple': 'red', 
    'banana': 'yellow', 
    'mango': 'orange'
}

for fruit, color in fruits.items():
    print(f'{fruit} is {color}')

This will output:

apple is red
banana is yellow
mango is orange

You can also use the enumerate() function to iterate over the keys and values of a dictionary, like this:

for fruit_index, (fruit, color) in enumerate(fruits.items()):
    print(f'{fruit_index}. {fruit} is {color}')

This will output:

0. apple is red
1. banana is yellow
2. mango is orange

How Do I Repeat A Code In Python Forever?

To repeat a code in Python forever, you can use a while loop with a condition that is always True.

Here is an example of a forever loop in Python:

while True:
    print('I\'m repeating forever!')

This loop will run indefinitely, printing the message “I’m repeating forever!” over and over again.

It is important to be careful when using forever loops, as they can cause your program to run indefinitely if you do not include a way to exit the loop.

For example, you might want to include a condition that allows the loop to break when a certain condition is met, like this:

while True:
    print('I\'m repeating forever!')

    # check for exit condition
    if some_condition:
        break

This will allow the loop to exit when the some_condition is True.

Here is an example of a while loop in Python with a condition that allows the loop to exit when a certain number of iterations have been reached:

count = 0
max_count = 10

while count < max_count:
    print(f'Iteration: {count}')
    count += 1

print('Exiting loop.')

This loop will iterate 10 times, printing the current iteration number each time, and then exit and print “Exiting loop.”

The output of this code would be:

Iteration: 0
Iteration: 1
Iteration: 2
Iteration: 3
Iteration: 4
Iteration: 5
Iteration: 6
Iteration: 7
Iteration: 8
Iteration: 9
Exiting loop.

Frequently Asked Questions (FAQs)

What Is A For Statement In Python?

In Python, a for statement is used to iterate over a sequence of elements, such as a list or a string.

The for statement allows you to execute a block of code for each element in the sequence.

Here is the basic syntax for a for statement in Python:

for variable in iterable:
    # code to be executed

The variable is a placeholder for each item in the iterable.

The for loop will execute the code block inside of it for each item in the iterable.

Python code examples were given earlier in the post.

You can use the for statement to iterate over any iterable object in Python, such as a list, a string, or a dictionary.

Do For Loops Always Start With 0 Python?

No, for loops in Python do not always start with 0.

The starting index of a for loop is determined by the sequence that it is iterating over.

For example, consider the following code:

numbers = [1, 2, 3, 4, 5]

for number_index in range(len(numbers)):
    print(
        f'number_index: {number_index}, '
        f'number: {numbers[number_index]}'
    )

This for loop will iterate over the indices of the numbers list, starting from 0 and ending at len(numbers) - 1.

For each iteration, the value of the current index will be assigned to the i variable, and the code block inside the loop will be executed, which in this case is a single line that prints the element at index i of the numbers list.

The output of this code will be:

number_index: 0, number: 1
number_index: 1, number: 2
number_index: 2, number: 3
number_index: 3, number: 4
number_index: 4, number: 5

If you want index to start with 1 or any other number, look for code examples somewhere above in this post.

How To Loop A String In Python?

To loop over the characters of a string in Python, you can use a for loop.

Here is an example of how to do this:

string = 'Hello, World!'
for ch in string:
    print(ch)

This for loop will iterate over the characters in the string variable, starting with the first character and ending with the last.

For each iteration, the value of the current character will be assigned to the ch variable, and the code block inside the loop will be executed, which in this case is a single line that prints the value of ch.

The output of this code will be:

H
e
l
l
o
,
 
W
o
r
l
d
!