Exploding by Array of Delimiters

Question

Is there any way to explode() using an array of delimiters?

PHP Manual:

array explode ( string $delimiter , string $string [, int $limit ] )

Instead of using string $delimiter is there any way to use array $delimiter without affecting performance too much?

Answer 1

$str = 'Monsters are SUPER scary, bro!';
$del = array('a', 'b', 'c');

// In one fell swoop...
$arr = explode( $del[0], str_replace($del, $del[0], $str) );

Answer 2

Use preg_split() with an appropriate regex.

Answer 3

function explode_by_array($delim, $input) {
  $unidelim = $delim[0];
  $step_01 = str_replace($delim, $unidelim, $input); //Extra step to create a uniform value
  return explode($unidelim, $step_01);
}

That's improved @65Fbef05's code. We use first delimiter, because "+delim+" may be used in original string.

Answer 4

The above suggestions won't work if the delimiters after the first delimiter include characters from that first delimiter. For instance, if you want to use line breaks as delimiters, but you're not sure if your input uses \r\n, \r or just \n, you can't use the above methods.

$str = '___RN___RN___R___N___RN___RN';
$del = array('RN', 'R', 'N');

# This won't work if delimiters 2, 3, n include characters from delimiter 1
var_dump(explode( $del[0], str_replace($del, $del[0], $str)));

This will output:

array(11) {
  [0]=>
  string(4) "___R"
  [1]=>
  string(0) ""
  [2]=>
  string(4) "___R"
  [3]=>
  string(0) ""
  [4]=>
  string(4) "___R"
  [5]=>
  string(3) "___"
  [6]=>
  string(4) "___R"
  [7]=>
  string(0) ""
  [8]=>
  string(4) "___R"
  [9]=>
  string(0) ""
  [10]=>
  string(0) ""
}

Which isn't ideal if you're planning to do string comparisons. Instead, you'll need to get a bit more complex. What I have written below may not be the most efficient and succinct, but it does the trick.

# This, however, will work
function array_explode($delimiters, $string){
    if(!is_array(($delimiters)) && !is_array($string)){
        //if neither the delimiter nor the string are arrays
        return explode($delimiters,$string);
    } else if(!is_array($delimiters) && is_array($string)) {
        //if the delimiter is not an array but the string is
        foreach($string as $item){
            foreach(explode($delimiters, $item) as $sub_item){
                $items[] = $sub_item;
            }
        }
        return $items;
    } else if(is_array($delimiters) && !is_array($string)) {
        //if the delimiter is an array but the string is not
        $string_array[] = $string;
        foreach($delimiters as $delimiter){
            $string_array = array_explode($delimiter, $string_array);
        }
        return $string_array;
    }
}

var_dump(array_explode($del,$str));

It will output the following:

array(7) {
  [0]=>
  string(3) "___"
  [1]=>
  string(3) "___"
  [2]=>
  string(3) "___"
  [3]=>
  string(3) "___"
  [4]=>
  string(3) "___"
  [5]=>
  string(3) "___"
  [6]=>
  string(0) ""
}

Have a play: https://3v4l.org/bJOkI

Answer 5

php's explode method doesn't support multiple delimiters, so you can't pass it an array. Also, what kind of string are you parsing that has multiple delimiters? you're best bet would be to loop through your delimiters, and re-explode some of the exploded strings.