Conditional display of a key in the array

Question

How do I know if a key in an array is true? If not, then don't use this

[0] => array
(
[id] => 1
[some_key] => something
)

[1] => array
(
[id] => 2
)

[2] => array
(
[id] => 3
[some_key] => something
)

foreach($array as $value){
$id = $value->id;
if($value->some_key === TRUE){
$some_key = $value->some_key; //some may have this key, some may not
}
}

Not sure what is the proper statement to check if this array has that some_key. If I don't have a check, it will output an error message.

Thanks in advance.

Is it the keys you want to check for or the value? Because you keep saying keys, but your checking for a value. — Bradmage
– Bradmage, Commented Mar 11, 2012 at 9:07

DanRedux · Accepted Answer · 2012-03-11 08:58:04Z

2

Try

isset($array[$some_key])

It will return true if the array $array has an index $some_key, which can be a string or an integer.

answered Mar 11, 2012 at 8:58

DanRedux

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Comments

Dan Murfitt · Accepted Answer · 2012-03-11 09:08:31Z

1

You can use the isset() function to see if a variable is set.

foreach($array as $value){
    $id = $value->id;
    if(isset($value->some_key)){
        $some_key = $value->some_key;
    }
}

edited Mar 11, 2012 at 9:08

answered Mar 11, 2012 at 8:59

Dan Murfitt

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Comments

Nathan · Accepted Answer · 2012-03-11 09:03:41Z

1

Others have mentioned isset(), which mostly works. It will fail if the value under the key is null, however:

$test = array('sampleKey' => null);
isset($test['sampleKey']); // returns false

If this case is important for you to test, there's an explicit array_key_exists() function which handles it correctly:

http://php.net/manual/en/function.array-key-exists.php

answered Mar 11, 2012 at 9:03

Nathan

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1 Comment

Dan Murfitt Over a year ago

Good point. However, it's worth noting that this won't work on objects. For objects you need to use the property_exists() function: php.net/manual/en/function.property-exists.php

Bradmage · Accepted Answer · 2012-03-11 09:14:22Z

1

function validate($array)
{
    foreach($array as $val) {
        if( !array_key_exists('id', $val) ) return false;
        if( !array_key_exists('some_key', $val) ) return false;
    }
    return true;
}

answered Mar 11, 2012 at 9:14

Bradmage

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