I’m trying to filter a multidimensional array saved in a json file to output either all, none or just the arrays where one or more key values match each criteria set been declared in an array ($filter).
Some example filter array configurations could be:
department = marketing
The result should be all the jobs in the marketing department, or return an error for an empty array
department = marketing & location = london
The result should show all marketing jobs in london, or return an error for an empty array
location = london
The result should show all jobs in london, or return an error for an empty array
So the above describes my expected output, but what i find is the results will return any jobs for each filter criteria.
This can result in returning any jobs in a both department and location, as well as duplicate entries where all criteria are met.
This is my code. For the purpose of demoing the issue, I’ve output a basic example of the json file to the $data array.
<?php
$data = array(
0 => array (
'id' => 1,
'department' => 'web',
'location' => 'london'
),
1 => array (
'id' => 2,
'department' => 'marketing',
'location' => 'london'
),
2 => array (
'id' => 3,
'department' => 'web',
'location' => 'leeds'
),
3 => array (
'id' => 4,
'department' => 'marketing',
'location' => 'leeds'
),
);
$filter = array (
'location' => 'london',
'department' => 'marketing'
);
function check_data($arr, $k, $v) {
if (array_key_exists($k, $arr) && $arr[$k] === $v ) {
return $arr;
}
}
function filter_data($data, $filter) {
$result = array();
foreach($filter as $fk => $fv) {
foreach ($data as $key => $value) {
if (check_data($value, $fk, $fv) && check_data($value, $fk, $fv)) {
$result[] = check_data($value, $fk, $fv);
}
}
}
if(empty($filter)) {
return ($data);
}
return (empty($result)) ? 'error' : $result;
}
$results = filter_data($data, $filter);
echo '<pre>';
var_dump($results);
echo '</pre>';
if($results === 'error') {
print '<h1>No Results</h1>';
}
If i set just one criteria in the $filter array i get the expected output. 
$filter = array (
'location' => 'london'
);
If i set more than one criteria in the $filter array i get results for both criteria 
$filter = array (
'location' => 'london',
'department' => 'marketing'
);
If i set the value of one or more of multiple criteria to a value that won’t match, i still get results, rather than an error.
$filter = array (
'location' => 'beep',
'department' => 'marketing'
);
If i set all values for each criteria to value that won’t match, i get the expected error
$filter = array (
'location' => 'beep',
'department' => 'book'
);
Have i missed something, I’m not sure how to get around this issue? Any help would be greatly appreciated.
Thanks