What is a faster and more efficient way to check if a key exists in a PHP array?

Question

Consider these two examples...

$key = 'jim';

// example 1
if (isset($array[$key])) {
    // ...
}

// example 2    
if (array_key_exists($key, $array)) {
    // ...
}

I'm interested to know if these two are better. I've been using the first example, but I've seen a lot of people on this site using the second example.

So, which one is better? hurry up? Clearer intention?

Answer 1

If you are interested in some of the tests I recently completed:

https://stackoverflow.com/a/21759158/520857

Summary:

| Method Name                              | Run time             | Difference
=========================================================================================
| NonExistant::noCheckingTest()            | 0.86004090309143     | +18491.315775911%
| NonExistant::emptyTest()                 | 0.0046701431274414   | +0.95346080503016%
| NonExistant::isnullTest()                | 0.88424181938171     | +19014.461681183%
| NonExistant::issetTest()                 | 0.0046260356903076   | Fastest
| NonExistant::arrayKeyExistsTest()        | 1.9001779556274      | +209.73055713%

Answer 2

isset() is faster, but not the same as array_key_exists().

array_key_exists() Purely checks if the key exists, even if the value is NULL.

Given If the key exists and the value is NULL, isset() will return false.