is_numeric

(PHP 4, PHP 5, PHP 7)

is_numeric — Finds whether a variable is a number or a numeric string

Description

is_numeric ( mixed $var ) : bool

Finds whether the given variable is numeric. Numeric strings consist of optional whitespace, 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) and binary (e.g. 0b10100111001) notation is not allowed.

Parameters

var

The variable being evaluated.

Return Values

Returns TRUE if var is a number or a numeric string, FALSE otherwise.

Examples

Example #1 is_numeric() examples

<?php
$tests = array(
    "42",
    1337,
    0x539,
    02471,
    0b10100111001,
    1337e0,
    "0x539",
    "02471",
    "0b10100111001",
    "1337e0",
    "not numeric",
    array(),
    9.1,
    null
);

foreach ($tests as $element) {
    if (is_numeric($element)) {
        echo var_export($element, true) . " is numeric", PHP_EOL;
    } else {
        echo var_export($element, true) . " 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
1337.0 is numeric
'0x539' is NOT numeric
'02471' is numeric
'0b10100111001' is NOT numeric
'1337e0' is numeric
'not numeric' is NOT numeric
array (
) is NOT numeric
9.1 is numeric
NULL is NOT numeric

Changelog

Version Description
7.0.0 Strings in hexadecimal (e.g. 0xf4c3b00c) notation are no longer regarded as numeric strings, i.e. is_numeric() returns FALSE now.

See Also

  • ctype_digit() - Check for numeric character(s)
  • is_bool() - Finds out whether a variable is a boolean
  • is_null() - Finds whether a variable is NULL
  • is_float() - Finds whether the type of a variable is float
  • is_int() - Find whether the type of a variable is integer
  • is_string() - Find whether the type of a variable is string
  • is_object() - Finds whether a variable is an object
  • is_array() - Finds whether a variable is an array