CODEWITHSUNDEEP
php
Dany D
Dany D

Reputation: 1189

How to check multiples in php to abstract the following sequence of numbers

I have a for loop, and I want to write a function to abstract the following sequence:

1   2   3   4
5   6   7   8
9   10  11  12
13  14  15  16
.............

So, in a somewhat "pseudo" code, the function would have to check multiples like so:

$i = 0;

for (condition) {
    $i++

    if ($i is 1, 5, 9, 13) do something
    if ($i is 2, 6, 10, 14) do something
    if ($i is 3, 7, 11, 15) do something
    if ($i is 4, 8, 12, 16) do something
}

Any ideas?

Upvotes: 1

Views: 53

Answers (1)

greg0ire
greg0ire

Reputation: 23255

Use the modulo operator. 1, 5, 9 or 13 modulo 4 is always 1.

Also you may want to use a switch / case statement, to avoid repeating the modulo 4 part.

<?php
switch ($remainder = $i % 4) {
    case 0:
        // and do another thing too
    break;
    case 1:
        // do something
    break;
    case 2:
        // do something else
    break;
    case 3:
        // do yet another thing
    break;

    default:
        throw new \UnexpectedValueException(sprintf(
            'the remainder is %d, this is very strange!',
            $remainder
        ));
}

Upvotes: 1

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