Compare Dates from Array with multidimensional array [duplicate] - php

Question

I have a multidimensional array like this:
Array (
[0] => Array
(
[time] => 1364685993
[memberid] => 131
)
[1] => Array
(
[time] => 1364685994
[memberid] => 133
)
[2] => Array
(
[time] => 1364685995
[memberid] => 141
)
)
and a single-dimensional array like this:
Array (
[0] => 131
[1] => 141
[2] => 191
[3] => 205
)
Now I want to remove all Sub-arrays from multidimensional arrays that DOES NOT contain the memberid value from normal array ?
In this case only Subaray[1] to be removed from multidimensional array as it's 'memberid' key value (133) doesn't show in normal array. Those arrays are actually pretty big, so I am not sure what would be fastest way to do it ?

Answer 1

$normalArray = array_flip($normalArray);
$multiDimArray = array_filter($multiDimArray, function ($elem) use ($normalArray) {
return isset($normalArray[$elem['memberid']]);
});
Requires exactly two iterations, one over each array. Key lookups using $normalArray[$elem['memberId']] are blazingly fast. May have some memory overhead due to the functional nature and copies of arrays, use a traditional loop and unset if that's an issue.

Answer 2

First, I would flip the $nomal array to get constant lookup time into the array, like this:
$normal = array_flip( $normal);
Then, you just have to filter the $multidimensional_array by the $normal array with a simple lookup:
$filtered = array_filter( $multidimensional_array, function( $el) use( $normal) {
return isset( $normal[ $el['member_id'] ]);
});

Answer 3

Don't have access to development resources at the moment to test but this should work.
foreach($members as $member => $property) {
if (!in_array($property['member_id'], $id_array)) {
unset($members[$member]);
}
}
$id_array is the 1-dimensional matrix (array) you've put in your question.

Answer 4

Instead of filtering the database results after the fact you may want to use the single-dimensional array in the database query itself.
We do not know what the query, you are using, looks like, but something along these lines would do it:
// The ids from the file
$use_ids = array(131, 141, 191, 205);
// Create a list for the IN clause
$ids = '(' . implode(',', $use_ids) . ')';
// Create the query
$query = <<< SQL
SELECT time, memberid
FROM some_table
WHERE ...
AND memberid IN {$ids}
ORDER BY time
SQL;
// Execute the query, etc.
It is always a good idea to let the SQL handle as much filtering of content as possible.