How to use is_numeric() in PHP to determine whether a variable is a number or a numeric string

In the daily use of PHP, we often need to determine whether a variable is a number or a string of numbers. PHP provides us with a built-in Function is_numeric() helps us determine whether a variable is a number or a numeric string more efficiently.

Syntax:

bool is_numeric ( mixed $var )

• $var: Variables that need to be judged

• Return value: TRUE is returned if $var is a number or numeric string, otherwise FALSE is returned.

Usage example:

<?php
$var = array(666678,"a678","666678",null,+125689.66);

foreach ($var as $key => $value) {
    
    if(is_numeric($value)){

    print("参数是数字或数字字符串<br/>");
    }else{

    print("参数不是数字或数字字符串<br/>");
    }
}
?>

输出：
参数是数字或数字字符串
参数不是数字或数字字符串
参数是数字或数字字符串
参数不是数字或数字字符串
参数是数字或数字字符串

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