For

Run part of the program the number of times you say using an index variable.

for(let i = 0; i <= 4; ++i) {
    let j = i;
}

Example: Count to 4

This program will show the numbers 0, 1, 2, 3, and 4 one after another on the LED screen.

input.onButtonEvent(Button.A, input.buttonEventValue(ButtonEvent.Down), () => {
    for(let i = 0; i < 5; ++i) {
        basic.showNumber(i)
    }
})