Iteration counter for double loops

Question

I am trying to find the formula to count every iteration of this double for loop (in python for instance):

for i in range(5):
   for j in range(5):
       count = MYSTERIOUS_FORMULA
       print count

Here the final value of count should be 25.

I tried count=(i+1)*j but it produce 0,1,2,3,4,0,2,4 etc.

Answer 1

The Double-for-loop (a.k.a. Nested loops).

# Set count to 0 before loop starts
count = 0

for i in range(5):
    for j in range(5):
        # solved mysterious formula (short hand 'count = count + 1')
        count += 1
# displaying count after loop
print(count)

Expanding on the formula count = count + 1, this sets count to be equal itself + 1:

count = count + 1