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.
gmp_sign
(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)
gmp_sign — Sinal do número
Parâmetros
Valor Retornado
Retorna 1 se num for positivo,
-1 se num for negativo,
e 0 se num for zero.
Exemplos
Exemplo #1 Exemplo de gmp_sign()
<?php
// positivo
echo gmp_sign("500") . "\n";
// negativo
echo gmp_sign("-500") . "\n";
// zero
echo gmp_sign("0") . "\n";
?>O exemplo acima produzirá:
1 -1 0
add a note
User Contributed Notes 6 notes
thomas at zilliox dot me ¶
13 years ago
jdyerjdyer ¶
9 years ago
For conciseness or golfing ;)
$s=$n<0|-($n>0)
where $s sign is 1 if positive, -1 if negative, otherwise -0 or +0 which is still 0
Andrew Martin ¶
10 years ago
Another way for those without GMP:
<?php
function sign($number) {
return $number / abs($number ?: 1);
}
?>
