PHP - Add value to comma based string/array

Question

I am storing some data in my database in a comma based string like this:

value1, value2, value3, value4 etc...

This is the variables for the string:

$data["subscribers"];

I have a function which on users request can remove their value from the string or add it.

This is how I remove it:

    /* Remove value from comma seperated string */
    function removeFromString($str, $item) {
    $parts = explode(',', $str);

    while(($i = array_search($item, $parts)) !== false) {
        unset($parts[$i]);
    }

    return implode(',', $parts);
    }
    $newString = removeFromString($existArr, $userdata["id"]);

So in the above example, I am removing the $userdata['id'] from the string (if it exists).

My problem is.. how can I add a value to the comma based string?

Maybe it's just me, but I find it quite surprising that you can come up with the logic for removeFromString but is unable to do so for addToString. — light
– light, Commented Jun 21, 2015 at 15:26
This really isn't a good idea.... storing comma-separated values in a database always causes so many problems for people — Mark Baker
– Mark Baker, Commented Jun 21, 2015 at 16:09
Precisely the problems you're having: adding, modifying and deleting values from the set..... not to mention searching for records that have a specific value among the set of comma-separated values in that column (find me all the records that user 3 subscribes to) — Mark Baker
– Mark Baker, Commented Jun 21, 2015 at 17:48

David Mchedlishvili · Accepted Answer · 2017-11-22 13:02:12Z

3

Best performance for me

function addItem($str, $item) {
    return ($str != '' ? $str.',' : '').$item;
}

answered Nov 22, 2017 at 13:02

David Mchedlishvili

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Comments

Nelson Owalo · Accepted Answer · 2015-06-21 15:24:05Z

2

You can use $array[] = $var; simply do:

function addtoString($str, $item) {
    $parts = explode(',', $str);
    $parts[] = $item;

    return implode(',', $parts);
    }
    $newString = addtoString($existArr, $userdata["id"]);

answered Jun 21, 2015 at 15:24

Nelson Owalo

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Comments

Eduardo Escobar · Accepted Answer · 2015-06-21 15:25:56Z

1

function addToString($str, $item) {
    $parts = explode(',', $str);
    array_push($parts, $str);
    return implode(',', $parts);
}
$newString = addToString($existArr, $userdata["id"]);

edited Jun 21, 2015 at 15:25

answered Jun 21, 2015 at 15:21

Eduardo Escobar

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3 Comments

light Over a year ago

The function name should be addToString

Eduardo Escobar Over a year ago

Cool, from the version i proposed, just a minor change is needed to be done

Nelson Owalo Over a year ago

Note: If you use array_push() to add one element to the array it's better to use $array[] = because in that way there is no overhead of calling a function

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