php filter_var fails with zero on FILTER_VALIDATE_INT

Question

I'm confused the following throws an exception:

if (!filter_var(0, FILTER_VALIDATE_INT))
    throw new Exception("Non numeric field passed " . $field . " when expecting a number: " . $variable . " passed instead");

anything positive works fine? I've tried intval(0) and still nothing. is zero not an integer?

score 16 · Answer 1 · answered Aug 22 '14 at 11:56

16

People should test false instead:

if (filter_var($value, FILTER_VALIDATE_INT) === false) {
    // $value is not an integer
}

answered Aug 22 '14 at 11:56

datasn.io

12,564
28
113
154

But what if the input can range between 0 - 100000? – ii iml0sto1 Dec 30 '17 at 22:20
Another reason why the lack of type safety is literally trouble in this language. – Martin Braun Mar 07 '23 at 03:50

score 9 · Answer 2 · answered Mar 24 '14 at 07:16

9

filter_var Returns the filtered data, or FALSE if the filter fails.

filter_var(0, FILTER_VALIDATE_INT) returns int(0), and is a falsy value, !filter_var(0, FILTER_VALIDATE_INT) will be true.

answered Mar 24 '14 at 07:16

xdazz

158,678
38
247
274

But what if the input can range between 0 - 100000? – ii iml0sto1 Dec 30 '17 at 22:20
@iiiml0sto1 because of rand of Integer is -2^31 => 2^31, 0 - 100000 is a child of the aggregate – HoangHieu Aug 24 '18 at 16:30

php filter_var fails with zero on FILTER_VALIDATE_INT

2 Answers2

Linked

Related