For Loop

The next type of loop in Python is the for loop, which allows us to repeatedly execute a block of code for each element in an array. The for loop is often used when we know how many times we want to perform an operation or when we want to iterate through all elements in a sequence. On the other hand, the while loop is used when we do not know how many times we need to repeat the loop.

The structure of a for loop looks like this:

for element in array: # For each element in the array
    # Block of code to be executed for each element

element is a variable that holds the value of the element corresponding to the iteration of the loop. Practically speaking, during the first iteration of the loop, element is the first element of the array. During the second iteration of the loop, element is the second element of the array, and so on.

Example: We want to print all the elements in a list:

numbers = [1, 2, 3, 4, 5]
for number in numbers:
    print(number)
# Prints: 1 2 3 4 5

In this example, we go through all the elements in the numbers list, and for each number, we execute the block of code that prints the number. Step by step:

1. The numbers variable is set to the array [1, 2, 3, 4, 5].
2. The first iteration of the loop starts, so the number variable is set to the first element of the array: 1.
3. The number is printed, so 1 is printed.
4. The second iteration of the loop starts, so the number variable is set to the second element of the array: 2.
5. The number is printed, so 2 is printed.
6. This process continues until we reach the end of the array.

It is important to note that number is just a variable name we came up with. The program would work the same if we replaced number with x or any other name:

numbers = [1, 2, 3, 4, 5]
for x in numbers:
    print(x)
# Prints: 1 2 3 4 5