function to check if the value is int or float but not string in PHP

Question

Is there any build-in function to check the value is number, in any integral type, like int, float but not string. is_numeric return true for "2". should I check it by both is_int and is_float?

The function that I want should return "invalid value" when $a and $b are not number:

function myFunction($a, $b, $sign){}

Thanks, but is there any other number type in PHP? like double or decimal? — Aryan Firouzian
– Aryan Firouzian, Commented Jul 30, 2017 at 22:15
Why are you asking me? Read the manual: php.net/manual/en/language.types.php — Reactgular
– Reactgular, Commented Jul 30, 2017 at 22:16
gettype( $var ) returns double for floats, if I recall correctly. — ArtisticPhoenix
– ArtisticPhoenix, Commented Jul 30, 2017 at 22:20
is_numeric($value) && !is_string($value) is an alternative to the first comment. — localheinz
– localheinz, Commented Jul 30, 2017 at 22:28

ArtisticPhoenix · Accepted Answer · 2017-07-30 22:39:08Z

2

This isn't an answer per se, but this is too much to put in a comment:

function isFloatOrInt($var)
{
    $type = gettype($var);

    switch ($type) {
        case 'integer':
        case 'double':
            return true;
        case 'string':
            //check for number embedded in strings "1" "0.12"
            return preg_match('/^[0-9]+(?:\.[0-9]+)?$/', $var);
        default:
            return false;
}

Preg match can be useful here if you consider the string version of a number to still be a number.

You say

But not string

But does that mean this 'string' or this '10' instead of 10 for example, ie. a string that is also a number?

There is probably many ways to do this, but there are some edge cases so it's largely depends on your needs. For example is an octet a number to you 0777 or and exponent 12e4 or even Hexadecimal 0xf4c3b00c?

edited Jul 30, 2017 at 22:39

answered Jul 30, 2017 at 22:26

ArtisticPhoenix

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3 Comments

localheinz Over a year ago

This is definitely not the simplest solution.

ArtisticPhoenix Over a year ago

No but under certain situations is_numeric can return a number when you don't want it to, such as '102e8' which it may see as an exponent.

ArtisticPhoenix Over a year ago

It depends, it's not ok for say a phone number, or a zip code. I've seen excel transform phone numbers into exponents in csv files for example.

Aryan Firouzian · Accepted Answer · 2017-07-30 22:33:38Z

1

is_numeric($value) && !is_string($value)

this is what I was looking for

answered Jul 30, 2017 at 22:33

Aryan Firouzian

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