Replacing all occurrences of a array with index from the occurring array

Question

I'm sorry if the title might be a bit confusing. But here is my problem. I have the following array called classes:

Array
(
    [0] => Array
        (
            [Name] => BE1A
            [Department] => Emmen
        )
     etc.

And I have an array called Departments:

Array
(
    [0] => Array
        (
            [Name] => 3 Receptie Emmen
            [code] => Emmen
        )
    etc.

These arrays will be imported into my database. But first i need replace value department in array classes to the index of the row where classes.department==departments.code. This way I can link classes with departments by using a foreign key. So array classes should be:

 Array
    (
        [0] => Array
            (
                [Name] => BE1A
                [Department] => 0
            )
         etc.

Any ideas?

did you try using foreach on your classes array and on every element using array_search for code? or you can create an array from classes with key as index of classes array and value as department and then search via array_search on that array — Peter Pivarc
– Peter Pivarc, Commented Jun 28, 2013 at 13:53
I thought about it, but since i have thousands of rows that need to be processed daily, this doesn't seem to be a very efficient way(i think). — JasperJ
– JasperJ, Commented Jun 28, 2013 at 13:57

Aleks G · Accepted Answer · 2013-06-28 14:15:02Z

1

This may not be the most efficient code, but it does what you want. In case multiple entries in the $departments match, it'll take the index of the first one. If no matches found, it will assign value NULL.

$classes = array(
    array('Name' => 'BE1A', 'Department' => 'Emmen'),
    array('Name' => 'Something', 'Department' => 'Another'),
    array('Name' => 'Yet more', 'Department' => 'More'),
    array('Name' => 'Yet more again', 'Department' => 'Nothing')
);

$departments = array(
    array('Name' => '3 Receptie Emmen', 'code' => 'Emmen'),
    array('Name' => 'Something else', 'code' => 'Another'),
    array('Name' => 'More stuff', 'code' => 'More')
);


for($i=0; $i<count($classes); $i++) {
    $arr = array_filter($departments, function($dpt) use($classes, $i) {
        return ($dpt['code'] == $classes[$i]['Department']);
    });
    if(count($arr) > 0) {
        reset($arr);
        $classes[$i]['Department'] = key($arr);
    }
    else {
        $classes[$i]['Department'] = NULL;
    }
}

print_r($classes);

This will output:

Array
(
    [0] => Array
        (
            [Name] => BE1A
            [Department] => 0
        )

    [1] => Array
        (
            [Name] => Something
            [Department] => 1
        )

    [2] => Array
        (
            [Name] => Yet more
            [Department] => 2
        )

    [3] => Array
        (
            [Name] => Yet more again
            [Department] => -1
        )

)

Note that it uses closures for array_filter, therefore you need to have at least php 5.3 for this to work. If you don't, then you can remove the use($classes, $i) and add global $classes, $i; inside the comparison function.

edited Jun 28, 2013 at 14:15

answered Jun 28, 2013 at 14:06

Aleks G

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3 Comments

Aleks G Over a year ago

@JasperJ I expanded my answer slightly to cater for cases where departments array doesn't have a match for your code.

JasperJ Over a year ago

I am a bit scared about the code efficiency, but I'll use this at first. Thanks.

Aleks G Over a year ago

@JasperJ You need to benchmark it to be sure, however there's not really any other option except to loop over one array and find matches from the other.

AlexP · Accepted Answer · 2013-06-28 14:32:56Z

1

Late to this but you can use an array iterator:

$classes = array(
  array('name' => 'Class1', 'department' => 'xyz'),
  array('name' => 'Class2', 'department' => 'foo'),
  array('name' => 'Class3', 'department' => 'bar'),
);

$departments = array(
  array('name' => 'Department1 name', 'code' => 'xyz'),
  array('name' => 'Department2 name', 'code' => 'foo'),
  array('name' => 'Department3 name', 'code' => 'bar'),  
);


$test = new ArrayIterator($classes);
while ($test->valid()) {
  $class = $test->current();
  foreach($departments as $department) {
    if ($class['department'] == $department['code']) {
      $key = $test->key();
      $classes[$key]['department'] = $key;
    }
  }
  $test->next();
}

print_r($classes);

answered Jun 28, 2013 at 14:32

AlexP

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2 Comments

JasperJ Over a year ago

Thanks, this solution is way faster then the array_filter method. +1

AlexP Over a year ago

@JasperJ - No problem, you can change your accepted answer if you think mine works better

Anil Gupta · Accepted Answer · 2013-06-28 13:55:20Z

0

array are accessed trhough index value and you need to iterate through one of array and then uyou can use it's index to get value from other array

classes[$key]['department']==departments[$key]['code']

answered Jun 28, 2013 at 13:55

Anil Gupta

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1 Comment

JasperJ Over a year ago

Then how would i retrieve the index of departments while iterating through classes?

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