is_numeric
Checks whether a value is a number or a numeric string.
Syntax
is_numeric(mixed $value): boolParameters
| Parameter | Type | Description |
|---|---|---|
| $value | mixed | The value to check. |
Return value
bool`true` for numbers and strings that look like a number.
Examples
Numeric and non-numeric strings:
<?php
var_dump(is_numeric('42'));
var_dump(is_numeric('4.5'));
var_dump(is_numeric('4 kg'));Output:
bool(true)
bool(true)
bool(false)Checking before a calculation:
<?php
$input = '15';
echo is_numeric($input) ? $input * 2 : 'not a number';Output:
30Notes
The function also accepts forms such as 1e5 and -0.5. If you need exactly an integer, use filter_var($value, FILTER_VALIDATE_INT).
See also
- intval — Converts a value to an integer.
- gettype — Returns the name of a value's type.
- filter_var — Validates or sanitises a value by a given rule.
Related recipes
In the tutorial
- Numbers and maths — PHP's maths functions — rounding, number formatting, random numbers and the precision of fractions.