For Loop

Sometimes when programming, it's necessary to perform the same or almost the same operation a couple of times.

To prevent writing the same thing over and over again, we can use loops.

The for loop has the following syntax:

for i in range(start, end):
    code

The range(start, end) determines what is the start value and what is the end value. The i will receive all values from start to end (not including end) sequentially. For example:

for i in range(0, 5):
	print(i)

It will execute the print statement 5 times:

0
1
2
3
4

We can simplify the range(0, 5) to range(5):

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

You can also combine i with other text using an f-string. Place an f before the string and use {i} inside it to insert the value of i:

for i in range(1, 4):
	print(f"Item number: {i}")

This will print:

Item number: 1
Item number: 2
Item number: 3

Loops have many use cases. For example, let's sum all the numbers from 1 to 100:

sum_numbers = 0
for i in range(1, 101):
	sum_numbers += i
print(sum_numbers)

This will first loop through all numbers between 1 and 101 (not including 101) and sum all of them. Then it will print the sum_numbers variable.