How to Loop Through a Python List Using for and while

First, a list containing mixed types is defined and printed to show its structure:

list = ["a", 1, "b", 2]
print(list)

The output is ['a', 1, 'b', 2], confirming that Python lists can store heterogeneous elements.

To access each element sequentially, a for loop is used. The loop variable element receives one item from the list on each iteration, and print(element) outputs it:

list = ["a", 1, "b", 2]
for element in list:
    print(element)

The resulting lines are:

a
1
b
2

This demonstrates that the for construct automatically traverses the entire list without manual indexing.

Next, a while loop example shows how to repeat a block while a condition holds. The variable num starts at 0, and the loop continues while num < 5:

num = 0
while num < 5:
    num = num + 1
    print("Executed " + str(num) + " times")

During each iteration, num is incremented, then converted to a string with str(num) so it can be concatenated with other strings—an important step because Python does not allow direct concatenation of integers and strings.

The loop prints:

Executed 1 times
Executed 2 times
Executed 3 times
Executed 4 times
Executed 5 times

The article warns that the loop condition must eventually become false; otherwise the program would run indefinitely and could crash.