Multiple array function calls within php not returning as expected

Question

Note: This is a question about a technical exercise. Please focus on utilising the same or similar array functions that I require instead of separating the code out into obviously more readable, but longer code segments.

I'm attempting to use an array_filter() and an array_walk() together. I haven't used these functions much, so I would like to learn about them in the process.

I have an array of possible environment strings ('sandbox', 'live', 'dev')
I have a string containing chosen environment ('dev')
I have an array of filepaths using glob()

I need to retrieve a list of files, using glob, that don't contain the strings from the difference between the two environments.

I have the following starting variables:

$possible = array('dev', 'sandbox', 'live');
$env = array('dev');

And obviously the difference between the two:

$diff = array_diff($possible, $env); // array('sandbox', 'live')

The directory I'm trying to perform a glob() on contains the following:

array(
    0 => '/config/dev.yml',
    1 => '/config/sandbox.yml',
    2 => '/config/live.yml',
    3 => '/config/global.yml',
    4 => '/config/routes.yml',
    5 => '/config/security.yml'
);

I would like to use array function calls to return the following:

array(
    0 => '/config/dev.yml', // Because $env = 'dev'. Sandbox and live are removed
    1 => '/config/global.yml',
    2 => '/config/routes.yml',
    3 => '/config/security.yml
);

Notice how sandbox.yml and live.yml have been removed.

Here is the code I'm using:

/** Loop through the list of yml files, placing $file into the local scope each time around, also import $possible, $env, $diff **/
$result = array_filter(glob(dirname(__DIR__) . '/config/*.yml'), function ($file) use ($possible, $env, $diff) {
    /** Loop around the diff (sandbox, live), placing them into $d each time around, also import $file again **/
    return array_walk($diff, function($d) use ($file) {
        /** Return when each environment (sandbox, live) is NOT in the $file string **/
        return !strstr($file, $d); 
    });
});

My issue is: Whatever the inner-most return changes to, it doesn't change the result. I can return true or false in there and it doesn't make a difference. I get back a list of all the files, *including the one's containing the string "sandbox.yml" and "live.yml", which isn't what I want.

Where is my logic going wrong?

array_walk: “Returns TRUE on success or FALSE on failure.” Since there is no “failure”, but walking through the array works successfully, you get TRUE returned every time, and that means array_filter will keep all array elements. (returning a value from inside the array_walk callback function does not work as you expect it to.) — C3roe
– C3roe, Commented Oct 8, 2013 at 10:31
@CBroe Ah so I'm using the wrong array method then. Can you suggest an alternative (in an answer, if you like) that achieves what I'm after? Another array_filter() perhaps? — Jimbo
– Jimbo, Commented Oct 8, 2013 at 10:32

Ja͢ck · Accepted Answer · 2013-10-08 10:40:45Z

1

The function array_walk() returns true on success which is almost every time you call it, so nothing gets filtered. You could consider a simple foreach inside instead:

$result = array_filter($files, function ($file) use ($diff) {
    foreach ($diff as $env) {
        if (strstr($file, $env) !== false) {
            return false;
        }
    }
    return true;
});

Alternatively, as mentioned by yourself:

$result = array_filter($files, function ($file) use ($diff) {
    return !in_array(basename($file, '.yml'), $diff);
});

edited Oct 8, 2013 at 10:40

answered Oct 8, 2013 at 10:34

Ja͢ck

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2 Comments

Jimbo Over a year ago

Jack's the repwhore today! :P Alternative is, instead of the foreach, return !in_array(basename($file, '.yml' ), $diff); apparently. Thanks :-)

Ja͢ck Over a year ago

@Jimbo Yes, I would have wanted to use array_some() here ;-)

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