Dividing a integer equally in X parts

Question

I'm looking for a efficient way in PHP to divide a number in equal part. Number will always be integer (no float).

Let's say that I have an array $hours with values from "1" to "24" ($hours['1'], etc) and a variable $int containing an integer. What I want to acheive is spreading the value of $int equally in 24 parts so I can assing the value to each corresponding array entries. (Should the number be odd, the remaining would be added to the last or first values in the 24).

Regards,

Solution 1

Here's the algorithm you're looking for; it evenly spreads an integer N over K cells:

for i = 0 to K
    array[i] = N / K    # integer division

# divide up the remainder
for i = 0 to N mod K
    array[i] += 1

Solution 2

Try this code

<?php
$num = 400;
$val = floor($num/24);

for($i=0;$i<24;$i++) {
    $arr[$i] = $val;
}

$arr[0] += $num - array_sum($arr);
?>

Comments

[Jean-Philippe Murray]

There you go! I didn't for once think that I could do a for loop with the N / K operation as the condition to stop. I just learned something here, and it works marvelously ! Thank you !

[Fred Foo]

@Jean-PhilippeMurray: please check out the correction that Zombaya just made to my algorithm; the loop should run up to N mod K, not N / K.

[Jean-Philippe Murray]

Could you just explain me what is the difference between N mod K and N / K at the end? I don't seem to see any difference while testing the two solutions...

[Fred Foo]

@Jean-PhilippeMurray: then your test doesn't cover all the appropriate cases. When you divide N by K, you get a remainder of N mod K and that's what you need to "smear out" over the array. In some cases, e.g. N=3 and K=2, N/K == N mod K, but not in general.