Walking a list and counting

A list is a row of values in order: [3, -1, 0, 8]. Write for v in values and v takes the next element on each turn. You do not need to know how many there are; the loop ends when the list does.

1count = 0
2for v in values:
3    if v > 0:
4        count += 1
5return count

The counter pattern: start at 0, add one for every element that meets the condition. count += 1 is short for count = count + 1.

The same pattern collects a sum: total += v. The only difference is what you add inside the loop: 1 when counting, the element itself when summing.

Tasks