(PHP 4, PHP 5, PHP 7)
is_numeric — Finds whether a variable is a number or a numeric string
Finds whether the given variable is numeric. Numeric strings consist of optional sign, any number of digits, optional decimal part and optional exponential part. Thus +0123.45e6 is a valid numeric value. Hexadecimal (e.g. 0xf4c3b00c), Binary (e.g. 0b10100111001), Octal (e.g. 0777) notation is not allowed.
varThe variable being evaluated.
   Returns TRUE if var is a number or a numeric
   string, FALSE otherwise.
  
Example #1 is_numeric() examples
<?php
$tests = array(
    "42",
    1337,
    0x539,
    02471,
    0b10100111001,
    1337e0,
    "not numeric",
    array(),
    9.1
);
foreach ($tests as $element) {
    if (is_numeric($element)) {
        echo "'{$element}' is numeric", PHP_EOL;
    } else {
        echo "'{$element}' is NOT numeric", PHP_EOL;
    }
}
?>
The above example will output:
'42' is numeric '1337' is numeric '1337' is numeric '1337' is numeric '1337' is numeric '1337' is numeric 'not numeric' is NOT numeric 'Array' is NOT numeric '9.1' is numeric
| Version | Description | 
|---|---|
| 7.0.0 | Strings in hexadecimal (e.g. 0xf4c3b00c) notation are
        no longer regarded as numeric strings, i.e.
        is_numeric() returns FALSEnow. |