27 loop intuition

27.1 repeating something

Repeating something is the most easy loop. For example, writing your name 4 times in the screen.

Atilla
Atilla
Atilla
Atilla

We can accomplish above with loops in the python, while or for loops. We will see how they work.

27.2 increasing numbers

This is again very common loop type. For example, printing out numbers from 1 to 10. This requirement could be accomplished with while or for loops again.

27.3 summation number 1..N

We want to find find summation of 1..10.

1 = 1
1+2 = 3
1+2+3 = 6
1+2+3+4 = 10
1+2+3+4+5 = 15
1+2+3+4+5+6  = 21
1+2+3+4+5+6+7 = 28
1+2+3+4+5+6+7+8 = 36
1+2+3+4+5+6+7+8+9  = 45
1+2+3+4+5+6+7+8+9+10 = 55



 1       = 1
(1)  + 2 = 3
(3)  + 3 = 6
(6)  + 4 = 10
(10) + 5 = 15
(15) + 6 = 21
(21) + 7 = 28
(28) + 8 = 36
(36) + 9 = 45
(45) +10 = 55

If we write this in python code.

index = 1
total = 0
while index <= 10:
    total = total + index
    index = index + 1

print(total)

change it so that it works with 1..N

index = 1
last_number = 10
total = 0
while index <= last_number:
    total = total + index
    index = index + 1

print(total)