Why count(false) return 1?

Question

Do you know why <?= count(false) ?> returns 1?

possible duplicate of [count of false gives 1 and if of an empty array gives false. why?](http://stackoverflow.com/questions/3776882/count-of-false-gives-1-and-if-of-an-empty-array-gives-false-why) — mario, Mar 10 '13 at 21:20

score 27 · Accepted Answer · answered Mar 10 '13 at 20:59

27

It's specified behavior:

If var is not an array or an object with implemented Countable interface, 1 will be returned.

According to http://php.net/manual/en/function.count.php

answered Mar 10 '13 at 20:59

Chris Laplante

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...you beat me by 5 seconds, so i'll just give you the +1 – Daedalus Mar 10 '13 at 21:00
how to get 0 from count if there is not an array?? – Ritesh Jan 03 '14 at 11:11
@Ritesh how about `$count = $var != false ? count($var) : 0;`? – aesede Apr 21 '16 at 21:37

score 10 · Answer 2 · answered Mar 10 '13 at 20:59

10

Because false is also a value and if the count() does not get array but a valid variable it returns true which is 1.

$result = count(null);
// $result == 0

$result = count(false);
// $result == 1

answered Mar 10 '13 at 20:59

Starx

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"Random" comment: it's like how if(0) returns false and if(-1) returns true. – Scott Yang Mar 10 '13 at 21:17
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You're close: it doesn't return `true`. `count` is expecting an array and if `var` isn't one, it gets cast into an array. Since `false` is a valid value, it gets cast to an array with one element: an element with the the value `false`. http://justinsomnia.org/2007/12/in-php-countfalse-returns-1/ – Nick Pickering Mar 13 '13 at 17:34

score 3 · Answer 3 · answered Apr 06 '16 at 08:40

3

A nice way to remember this in your mind:

count(false) is basically the same as:
count ("one boolean"), and therefore there are "ONE" booleans as result.

answered Apr 06 '16 at 08:40

Pwncopter

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score 2 · Answer 4 · answered Dec 28 '13 at 20:19

It looks to me like PHP is preventing one from using count() to determine if an element is an array or an object. They have dedicated functions for this (is_array(), is_object()) and it may be tempting to naively use count() and check for a false condition to determine array or object. Instead, PHP makes non-objects, non-arrays return 1 (which is truthy) so that this method cannot be be naively used in this way (since 0 is a valid, falsy result for an empty array/object).

This may be the why behind the choice of value to be returned by the function in the situation you're describing.

He's not trying to determine if it's an array or object, he's trying to determine the length of the array and questioning why a 0-record or non-existent array is still returning 1. — jerebear, Sep 22 '17 at 05:10

Why count(false) return 1?

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