Checking TRUE/FALSE Boolean values (NOT equates)

[Xeoncross]

 

I am trying to figure out if a item is a STRICT true/false value (and not if an item EQUATES to true or false).

 

I want to allow items that are:

true
'true'
1
false
'false'
0

without allowing items that act as true/false values. (i.e. 'stringname' == true while null == false)

 

Now I can do something clunky like:

<?php
if($value === 'true' ||
        $value === true ||
        $value === 1 ||
        $value === 'false' ||
        $value === false ||
        $value === 0) {
        print 'value is a plain true/false value';
} else { 
        print 'value is something else';
}
?>

 

But who wants to do something like that?

 

Take the following code that doesn't quite work:

<?php
$myarray = array(
    'true', true, 1,
    'false', false, 0,
    'string', '', " "
);

foreach($myarray as $value) {
    
    print ((boolean)$value && $value !== 'false') ? 'true' : 'false';
    print "<br />\n";
}

?>
Which outputs :
true
true
true
false
false
false
true
false
true

I want to get the first 6 to equate to TRUE while getting the last 3 to equate to FALSE.

 

I don't care if the value is true or false - I just want to know IF it is true or false (boolean style).

 

Any ideas? 

 

 

 

[DarkWater]

Just use == and not ===.

[Xeoncross]

Just use == and not ===.

 

You didn't read the post. 

 

null == false (WRONG)

'' == false (WRONG)

'string_true' == true (WRONG)

array('true') == true (WRONG)

 

[DarkWater]

Okay, then use === and not ==. O_O

[Xeoncross]

Okay, then use === and not ==. O_O

 

This isn't as simple as you seem to think it is.

Either I didn't explain the problem like I should - or it is over your head.

 

Please re-read the whole thing and you will see I am looking for values that represent strict boolean values - not values that that are true or false.

[DarkWater]

I highly doubt it's over my head.  Explain it again.  I don't understand at all what you're actually asking.  === will work with strict booleans, not 0, NULL, 'lol', or anything.

 

if ($bool === true) {

echo "Boolean true.";

} else {

echo "Not boolean true.";

}

[Xeoncross]

 

This is NOT what I want to do as it will allow any value that is TRUE (not just 'true', true, and 1)

<?php
if ($bool === true) {
echo "Boolean true.";
} else {
echo "Not boolean true.";
}
?>

 

I only want to allow values that are === true || 'true' || 1 || false || 'false' || 0

 

<?php

if($value === 'true' || $value === true ||
$value === 1 || $value === 'false' ||
$value === false || $value === 0) {
    print 'this is a boolean value';
} else {
    print 'This might be equal to true or false - but it is NOT a boolean value';
}

?>

[DarkWater]

May I ask why? =/  There's no real way to do that other than the way you outlined earlier simply because those are all different values that in a set of other values that could be true. 

 

For example, without strict bounds like you showed in the original post, nothing stops "the", 42, or "superhero" from being "true". 

[kenrbnsn]

Does the following do what you're looking for?

<?php
function really_true_false($val) {
$ret = false;
switch (true) {
	case ($val === true):
	case ($val === 'true'):
	case ($val === 1);
	case ($val === false):
	case ($val === 'false');
	case ($val === 0);
		$ret = true;
		break;
}
return ($ret);
}
$myarray = array(
    'true', true, 1,
    'false', false, 0,
    'string', '', " "
);
foreach ($myarray as $tst) 
echo (really_true_false($tst))?'true<br>':'false<br>';
?>

 

Ken

[Xeoncross]

May I ask why? =/ 

 

When dealing with php ini files the following values do NOT need quotes around them:

 

true

1

false

0

on

off

 

However, everything else in a PHP ini file is a string (except sections). Therefore the values "false" and false both need to be treated as a boolean (0) FALSE when working with ini files and not as strings.