CODEWITHSUNDEEP
phpregex
user6434562
user6434562

Reputation:

PHP preg_match doesn't match list separated with commas

Here's my users list

james,john,mark,luke,

james,john,mark,luke,mary,david

I want to remove the repeated part and retain the remaining.

So here's my code

$old   = 'james,john,mark,luke,';
$users = 'james,john,mark,luke,mary,david';

// Replace , with |
$expr = rtrim(preg_replace('/\,/', '|', $old), '|');

$newstr = preg_replace("/$expr/i", '', $users);

echo $newstr;

Output

,,,,mary,david

I want

mary,david,

Upvotes: 1

Views: 119

Answers (2)

Sebastian Brosch
Sebastian Brosch

Reputation: 43574

A solution, based on your code using trim:

$old = 'james,john,mark,luke,';
$users = 'james,john,mark,luke,mary,david';

$expr = rtrim(preg_replace('/\,/', '|', $old), '|');
$newstr = preg_replace("/$expr/i", '', $users);
echo trim($newstr, ',');

Demo: https://3v4l.org/W3XKe

A better solution using explode, array_diff and implode:

$old = 'james,john,mark,luke,';
$users = 'james,john,mark,luke,mary,david';

$old_items = explode(',', $old);
$users_items = explode(',', $users);

echo implode(array_diff($users_items, $old_items), ',');

Demo: https://3v4l.org/tnt9F

Upvotes: 2

eol
eol

Reputation: 24555

Can't test it right now, but wouldn't it work simply like that?

$old   = 'james,john,mark,luke,';
$users = 'james,john,mark,luke,mary,david';
echo preg_replace("/$old/", "", $users); //should print "mary,david"

Upvotes: 0

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