(PHP 4 >= 4.0.4, PHP 5)
gmp_sign — Sign of number
$a
)Checks the sign of a number.
a
可以是一个 GMP 数据 resouce，或一个可以转换为数值的字符串。
Returns 1 if a is positive,
-1 if a is negative,
and 0 if a is zero.
Example #1 gmp_sign() example
<?php
// positive
echo gmp_sign("500") . "\n";
// negative
echo gmp_sign("-500") . "\n";
// zero
echo gmp_sign("0") . "\n";
?>
以上例程会输出：
1 -1 0
thomas at zilliox dot me (2011-10-21 03:11:35)
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.