gmp_sign

(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

gmp_sign — Sign of number

说明

gmp_sign(GMP|int|string $num): int

Checks the sign of a number.

参数

num: Either a GMP object, or a numeric string provided that it is possible to convert the latter to an int.

返回值

Returns 1 if num is positive, -1 if num is negative, and 0 if num is zero.

示例

示例 #1 gmp_sign() example

<?php
// positive
echo gmp_sign("500") . "\n";

// negative
echo gmp_sign("-500") . "\n";

// zero
echo gmp_sign("0") . "\n";
?>

以上示例会输出：

1
-1
0

参见

gmp_abs() - Absolute value
abs() - 绝对值

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用户贡献的备注 2 notes

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thomas at zilliox dot me ¶

13 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.

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Andrew Martin ¶

7 years ago

Using a spaceship in PHP7:

<?php
$sign = $number <=> 0;
?>