Numeric Separators Inside A String?

<?php

echo 1_2_3;

$a = '1_2_3';

// warning: a non-numeric value encountered
echo $a + 0;   // 1
echo (int) $a; // 1
$int = eval("return $a;");

Since PHP 7.4, there are numeric separators, to make integers more readable.

They are only for hard-coded literals, so what do you do if you have stored them in a string?

The solution is to rely on eval(), with a trick : $int = eval('return '.$a.';');. return is important to return the value that was generated by the code.

Another option is to remove the underscore _ chars, and cast the value to int.

See Also

• strtr()

• numeric separator in strings [Try me]

PHP Features

• integer

• numeric-separator

• dynamic-call

• eval

• cast

• underscore

Last updated: 16 July 2026