Converting to Boolean Value in PHP

Question

Possible Duplicate:
How to Convert Boolean to String

I think that asking this might be kind of silly but I'm still wondering whether there is built-in way to return false or true as they way they look instead of 0 or 1, well actually this code even doesn't write 0 but 1:

<?php
$array = array(1,2,3);
echo (bool) $array;
?>

So I want this code to write "true" or "false" instead of numeric values. I know I can build a function but my curiosity likes to learn a built-in way if there is any.

score 7 · Accepted Answer · edited Feb 04 '12 at 19:24

7

Simply use the conditional operator:

echo (true ? 'true' : 'false');
echo (false ? 'true' : 'false');

Demo: http://codepad.org/hNHhXnBv

edited Feb 04 '12 at 19:24

Lightness Races in Orbit

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answered Feb 04 '12 at 19:17

TimWolla

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score 5 · Answer 2 · answered Feb 04 '12 at 19:16

5

echoing a boolean will always print either 0 or 1. Instead, use var_dump().

Another option is to echo 'true' or 'false' based on the value:

echo ((bool)$array) ? 'true' : 'false'

answered Feb 04 '12 at 19:16

Madara's Ghost

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what about to echo them actually and see? – Your Common Sense Feb 04 '12 at 19:18
so, does it *really* prints 0 and 1? – Your Common Sense Feb 04 '12 at 19:21
@Col.Shrapnel: What are you talking about? – Lightness Races in Orbit Feb 04 '12 at 19:24
@Light I am asking if PHP "always print either 0 or 1 when eching a boolean" – Your Common Sense Feb 04 '12 at 19:32
also, casting explicitly would be an overkill. `($array)` is enough. – Your Common Sense Feb 04 '12 at 19:41
@Col.Shrapnel: The answer is yes, and that's why the OP is here asking how to change that behaviour. Did you try it? – Lightness Races in Orbit Feb 04 '12 at 20:27
@Light the answer is no. echoing a boolean won't print 0 for false. – Your Common Sense Feb 04 '12 at 20:54
@Col.Shrapnel: No. It will echo nothing for false. True yields `1`. http://ideone.com/WpLc9 – Lightness Races in Orbit Feb 05 '12 at 02:02
@Light well, I don't know what to say. Thank you for your effort in trying to enlighten me. – Your Common Sense Feb 05 '12 at 06:35

score 1 · Answer 3 · answered Feb 04 '12 at 19:18

1

var_export() prints type and result.

echo var_export((bool)$array, 1);

answered Feb 04 '12 at 19:18

powtac

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score 0 · Answer 4 · answered Feb 04 '12 at 19:21

0

I think the main problem is to convert the array ELEMENTS to booleans, not the array as a whole.

You could use the function array_map for this.

function conv2bool($i) { return (bool) $i; }

$int_array = array(0,1,0,2,3);
$bool_array = array_map("conv2bool", $int_array);

var_dump($bool_array);

...this will return:

array(5) { [0]=> bool(false) [1]=> bool(true) [2]=> bool(false) [3]=> bool(true) [4]=> bool(true) }

answered Feb 04 '12 at 19:21

Mira Weller

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What do you mean by that? I've tried this code and it does exactly what I said. – Mira Weller Feb 04 '12 at 19:34
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your assumption, I believe. It's wrong. – Your Common Sense Feb 04 '12 at 19:43
But it doesn't make any sense at all to convert a whole `array` to a single `boolean`?! This would just give you false if the array is empty and true otherwise, I suppose. – Mira Weller Feb 04 '12 at 19:47
@MaxWeller: Yes, which makes perfect sense if that's what you want to do... – Lightness Races in Orbit Feb 04 '12 at 20:29

Converting to Boolean Value in PHP

4 Answers4