Are there any way to check exitency of an array key inside the function

Question

I have a project that I need to echo $variable['key'];

Some times $variable['key'] is not exist. And Those variables creates errors when I echo $variable['key']; directly.

My current method is

echo (isset($variable['key'])) ? $variable['key'] : '';

And this is not very efficient way of doing that. I do not want to write all keys two times.

I need a function. Basically That checks the $varible['key']; inside the function and returns the value of it.

function get_ifisset(&$var = null){
if(isset($var)){ return $var; }
}

echo get_ifisset($vars['key']);

but because of $variable['key'] is not exist I can not send them inside to the function

This kind of usage throws error which is "undefined key".

Also following function is an another approach that I dont like.

function get_ifisset($var, $key){
if(array_key_exists($key, $GLOBALS[$var])){ return $GLOBALS[$var][$key]; }
}

I would like to learn Are there any way to check exitency of an array key inside the function.

property_exists(); array_key_exists(); isset();

Whats the problem is with the "another approach"? Why don't you like that? — vaso123, Dec 16 '14 at 11:22
there is two ways to do it: use `isset` like a good boy or disable `E_NOTICE` warnings (this is bad) — Peter, Dec 16 '14 at 11:22
I'll be honest. I supress E_NOTICE warnings. I know this is BAD practice but I don't care. My life is much much easier. If you are not lazy **** as me use `isset()` everywhere. — Peter, Dec 16 '14 at 11:24
@lolka_bolka I do not like because I can not check $var['notexist']['notexistanother']; with that. This also throws error : undefined index. — Deniz Porsuk, Dec 16 '14 at 11:26
@DenizPorsuk - that's why you use `isset($var['key']) && isset($var['key']['another'])`. However, if you want to chain such an expression, Peter provided a proper answer. — N.B., Dec 16 '14 at 11:48

score 1 · Answer 1 · answered Dec 16 '14 at 11:27

1

You can pass array, key and default value to function:

public function getValue($array, $key, $default = '') {
    return isset($array[$key]) ? $array[$key] : $default;
}

$this->getValue($variable, 'key');

Also, from my experience function get_ifisset(&$var) does not throw any error (I have not set it default to null).

answered Dec 16 '14 at 11:27

Justinas

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Thank you for answer but these kind of approach also can not checks for $var['notexist']['notexistanother']; if I try to send $this->getValue($var['notexist'], 'notexistanother') – Deniz Porsuk Dec 16 '14 at 11:30
1

@DenizPorsuk you can modify if you pass `$key` as array it will check multi-dimensional key. for example `getValue($array, Array("key", "subkey", "subsubkey"), "");` – Peter Dec 16 '14 at 11:31
@Peter this is really not a bad idea. – Deniz Porsuk Dec 16 '14 at 11:36

score 1 · Answer 2 · answered Dec 16 '14 at 11:34

1

modified @Justinas function:

public function getValue($array, $key, $default = '') {
    if(!is_array($key)) {
        return isset($array[$key]) ? $array[$key] : $default;
    }
    $arr = & $array;
    foreach($key as $subkey) {
        if(!isset($arr[$subkey])) {
            return $default;
        }
        $arr = & $arr[$subkey];
    }
    return $arr;
}

so you can use it on multidimensional arrays

getValue($array, "key");

getValue($array, Array("key", "subkey", "subsubkey"));

answered Dec 16 '14 at 11:34

Peter

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It works for print_r(getValue($test['key'], Array("key2"))); http://ideone.com/juDXyg but not for print_r(getValue($test['notexist'], Array("key2"))); http://ideone.com/O03LRD – Deniz Porsuk Dec 16 '14 at 11:53
@DenizPorsuk this is how you should use it... http://ideone.com/1MeeBf because that was the point... – Peter Dec 16 '14 at 12:07

Are there any way to check exitency of an array key inside the function

2 Answers2