strcmp equivelant for integers (intcmp) in PHP

Question

So we got this function in PHP

strcmp(string $1,string $2) // returns -1,0, or 1;

We Do not however, have an intcmp(); So i created one:

Answer 1

At a glance, yes it feels dirty. Except there must be a good reason you wrote that instead of just using the actual ==, >, and < operators. What was the motivation for creating this function?

If it were me, I'd probably just do something like:

$x = $a==$b ? 0 : ($a>$b ? 1 : ($a<$b ? -1 : null));

I realize this is just as ugly, and the : null; - not sure if PHP requires it or if I could have just done :; but I don't like it and that code should never execute anyway... I think I'd be a lot less confused about this if I knew the original requirements!

Answer 2

Sort your data with:

function sortScripts($a, $b)
{
    return $a['order'] - $b['order'];
}

Use $b-$a if you want the reversed order.

If the numbers in question exceed PHP's integer range, return ($a < $b) ? -1 : (($a > $b) ? 1 : 0) is more robust.

Answer 3

why reinventing the wheel? http://php.net/manual/en/function.strnatcmp.php

echo strnatcmp(1, 2) . PHP_EOL; // -1
echo strnatcmp(10, 2) . PHP_EOL; // 1
echo strnatcmp(10.5, 2) . PHP_EOL; // 1 - work with float numbers
echo strnatcmp(1, -2) . PHP_EOL; // 1 - work with negative numbers

Test it here: https://3v4l.org/pSANR

Answer 4

Purely as some additional information, there has been an accepted RFC for this (https://wiki.php.net/rfc/combined-comparison-operator).

So, the comparison function would be along the lines of ...

<?php
$data = [...];
usort($data, function($left, $right){ return $left <=> $right; });
?>

A few really nice feature here is that the comparison is done in exactly the same way as all other comparisons. So type juggling will happen as expected.

As yet, there is no magic __forCompare() like method to allow an object to expose a comparison value. The current proposal (a different RFC) is to have each object be injected into every other object during the comparison so that it does the comparison - something which just seems odd to me - potential opportunity for recursion and stack overflow ... ! I would have thought either injecting the type of object for comparison (allowing an object the ability to represent appropriate values depending upon the type of comparison) or a blind request for a value that the object can serve up for comparison, would have been a safer solution.

Not yet integrated into PHP-NG (PHP 7 at the moment), but hopefully will be soon.

Answer 5

For strings

 usort($points, function ($a, $b) use ($orderFlag, $key1, $key2) {
        return strcmp($a[$key1][$key2], $b[$key1][$key2]) * $orderFlag;
    });

orderFlag => 1 (ascending): -1 (descending)

For numbers

usort($points, function ($a, $b) use ($orderFlag, $key1, $key2) {
    return ($a[$key1][$key2] - $b[$key1][$key2]) * $orderFlag;
});

orderFlag => 1 (ascending): -1 (descending)

Answer 6

Does it have to be +1 and -1? If not, just return (int) $a - (int) $b. I don't like the divide that someone else recommended, and there's no need to check for all three cases. If it's not greater and not equal, it must be less than.

return (int) $a > (int) $b ? 1 : (int) $a == (int) $b ? 0 : -1;