Using a spaceship in PHP7:
<?php
$sign = $number <=> 0;
?>
gmp_sign
(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)
gmp_sign — Segno di un numero
Descrizione
gmp_sign(resource
$a): int
Restituisce il segno di a : 1 se
a è positivo e -1 se è negativo.
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User Contributed Notes 7 notes
thomas at zilliox dot me ¶
11 years ago
Hi !
If you don't have the GMP extension, the sign function is really simple to code.
Here an example of implementation :
<?php
function sign( $number ) {
return ( $number > 0 ) ? 1 : ( ( $number < 0 ) ? -1 : 0 );
}
echo sign( 500 ); // Return 1
echo sign( -500 ); // Return -1
echo sign( 0 ); // Return 0
?>
Thomas.
jdyerjdyer ¶
7 years ago
For conciseness or golfing ;)
$s=$n<0|-($n>0)
where $s sign is 1 if positive, -1 if negative, otherwise -0 or +0 which is still 0
Andrew Martin ¶
8 years ago
Another way for those without GMP:
<?php
function sign($number) {
return $number / abs($number ?: 1);
}
?>
