is_numeric

定義和用法

is_numeric()函數用於檢查變量是否為數字或數字字符串。

如果變量是數字或數字字符串，則此函數返回true (1)，否則返回false /無返回值。

實例

檢查變量是否為數字或數字字符串：

 <?php
$a = 32 ;
echo "a is " . is_numeric ( $a ) . "<br>" ;

$b = 0 ;
echo "b is " . is_numeric ( $b ) . "<br>" ;

$c = 32.5 ;
echo "c is " . is_numeric ( $c ) . "<br>" ;

$d = "32" ;
echo "d is " . is_numeric ( $d ) . "<br>" ;

$e = true ;
echo "e is " . is_numeric ( $e ) . "<br>" ;

$f = null ;
echo "f is " . is_numeric ( $f ) . "<br>" ;
?>

親自試一試

文法

is_numeric ( variable ) ;