Multiple array_filter and strpos

Question

I want to return array that does not contains a list of characters.

Below code works fine for one keyword ('bc').

$array = array("abc", "def", "ghi");
$filterArray = array_filter($array, function ($var) {return(strpos($var, 'bc') === false);});
print_r($filterArray);

However, below code does not work when I try to filter out multiple keywords by using $excludeKeyword_arr and foreach.

$array = array("abc", "def", "ghi");
$excludeKeyword_arr = ("ab", "de");
foreach($excludeKeyword_arr as $exclude){
    $filterArray = array_filter($array, function ($var) {return(strpos($var, $exclude) === false);});
}
print_r($filterArray);

It should be return array instead of boolean type.

https://stackoverflow.com/questions/10589921/remove-elements-of-one-array-if-it-is-found-in-another — Abdur Rahman, Jan 05 '19 at 08:31

score 1 · Answer 1 · answered Jan 05 '19 at 08:41

There are 2 problems with the code. The first is that the scope of $exclude doesn't allow the closure to access it, simply solved by passing it in with use.

The second problem is that you always filter the original array ($array) and so the accumulative effect isn't achieved. So here I copy the array and keep on filtering the copy ($filterArray = array_filter($filterArray, function)...

$array = array("abc", "def", "ghi");
$excludeKeyword_arr = array("ab", "de");
$filterArray = $array;
foreach($excludeKeyword_arr as $exclude){
    $filterArray = array_filter($filterArray, function ($var) use ($exclude) 
                     {return(strpos($var, $exclude) === false);});
}
print_r($filterArray);

which results in

Array
(
    [2] => ghi
)

Andreas · Answer 2 · 2019-01-05T09:50:59.617

1

You can use preg_grep which will do the opposite and match the ones that has bc or de then array_diff.

$array = array("abc", "def", "ghi");
$excludeKeyword_arr = array("bc", "de");
$exclude_values = preg_grep("/". implode("|", $excludeKeyword_arr) . "/", $array);
$filterArray = array_diff($array, $values_with_bc);

print_r($filterArray); // [ 2 => "ghi"]

https://3v4l.org/IpNal

edited Jan 05 '19 at 09:50

answered Jan 05 '19 at 08:53

Andreas

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1

You need to change `$values_with_bc`, also update the *the ones that has **bc** or de then* – Nigel Ren Jan 05 '19 at 09:02

score 0 · Answer 3 · answered Jan 28 '20 at 09:10

For best performance, use a foreach() loop with a conditional break -- this way php doesn't need to perform useless iterations.

If the substring is found anywhere in the haystack string, remove it from the array of haystacks using unset().

Code: (Demo)

$array = ["abc", "def", "ghi"];
$excludeKeyword_arr = ["ab", "de"];

foreach ($array as $index => $haystack) {
    foreach ($excludeKeyword_arr as $needle) {
        if (strpos($haystack, $needle) !== false) {
            unset($array[$index]);
            break;
        }
    }
}
var_export(array_values($array));

Output:

array (
  0 => 'ghi',
)

A word of caution: if entertaining the notion of a preg_ call for brevity's sake, understand that for reliability/stability, you must apply preg_quote() to each values in the needles array if there is any chance of characters with special meaning to the regex engine.

JeFF - JXG · Answer 4 · 2020-02-09T22:42:30.430

I would do the same as @Andreas, but reindexing in the end.

$array           = ["ab", "def", "ghi"];
$excludeKeywords = ["ab", "de"];

$pattern = implode("|", $excludeKeywords);
$result = preg_grep("/$pattern/i", $array);

// Positive (Reindex)
print_r(array_values($result));

// Negative (Reindex)
$result = array_diff($array, $result);
print_r(array_values($result));

Multiple array_filter and strpos

4 Answers4

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