Convert a comma-separated string of key=value expressions into an associative array

Question

I have a string like this:

key=value, key2=value2

and I would like to parse it into something like this:

array(
  "key" => "value",
  "key2" => "value2"
)

I could do something like

$parts = explode(",", $string)
$parts = array_map("trim", $parts);
foreach($parts as $currentPart)
{
    list($key, $value) = explode("=", $currentPart);
    $keyValues[$key] = $value;
}

But this seems ridiciulous. There must be some way to do this smarter with PHP right?

Basilisk

Where does your data come from? Do you control how it is stored? Is it supposed to be a human readable (and writable) format? – Mounting

Answer 1

If you don't mind using regex ...

$str = "key=value, key2=value2";
preg_match_all("/([^,= ]+)=([^,= ]+)/", $str, $r); 
$result = array_combine($r[1], $r[2]);
var_dump($result);

Irrupt

however... using explode and loop like in the OP example will more than likely prove to be more efficient than using regex to parse it. – Furey

You never know that before you benchmark it. It heavily depends on the usage pattern. – Irrupt

I just had to use this. You nailed it! – Gastrotrich

I have $selectedSoftware = array("AntiVirus ($20)","Norton ($100)"); $n = implode(',',$selectedSoftware); $bool = preg_match_all("/([^,]+) (\$(\d+))/", $n, $matches); and it returns 0 can't figure out why, i tested it here phpliveregex.com/p/by8 – Adagio

Answer 2

<?php parse_str(str_replace(", ", "&", "key=value, key2=value2"), $array); ?>

Eckart

Beware this breaks if key or value contains an ampersand (&) – Domiciliate

Answer 3

if you change your string to use & instead of , as the delimiter, you can use parse_str()

Furey

Answer 4

If you can change the format of the string to conform to a URL query string (using & instead of ,, among other things, you can use parse_str. Be sure to use the two parameter option.

Condemnation

Answer 5

Here's a single command solution using array_reduce formatted in multple lines for readability:

<?php
$str = "key=value, key2=value2";
$result = array_reduce(
   explode(',', $str), 
   function ($carry, $kvp) {
      list($key, $value)=explode('=', $kvp); 
      $carry[trim($key)]=trim($value); 
      return $carry;
    }, []);

Undeviating

Answer 6

To cover a fringe case not expressed in this question, but expressed by a page closed by this page, you may need to allow key=value expression-separating characters to be part of the values (such as spaces and commas). In this case, use negated lookaheads to ensure the matched value is not actually part of the next key-value expression and use a lookahead to match the delimiting character(s) or the end of the string.

Code: (Demo)

$test = 'key=value, key2=va, lue 2, key3=value3';


preg_match_all("/(\w+)=((?:(?!\w+=.).)+)(?:, ?|$)/", $test, $m); 
var_export(
    array_combine($m[1], $m[2])
);

Output:

array (
  'key' => 'value',
  'key2' => 'va, lue 2',
  'key3' => 'value3',
)

Fremd