How do for loops work?

For loops are used to iterate over a sequence (like a list, tuple, string, or range) and execute a block of code multiple times, once for each item in the sequence. Here's how they work:

Basic Structure

In Python, a for loop has the following structure:

for variable in sequence:
    # code to execute for each item

How It Works

1. Initialization: The loop starts by taking the first item from the sequence and assigning it to the variable.
2. Execution: The code block inside the loop is executed using the current value of the variable.
3. Iteration: The loop then moves to the next item in the sequence and repeats steps 2 and 3 until all items have been processed.

Example

Here's a simple example that prints each number in a list:

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

for number in numbers:
    print(number)

Output:

1
2
3
4
5

Using range()

You can also use for loops with the range() function to iterate over a sequence of numbers:

for i in range(5):  # Iterates from 0 to 4
    print(i)

Output:

0
1
2
3
4

Summary

For loops are powerful for automating repetitive tasks and processing items in a collection. If you have more questions or need further examples, feel free to ask!