How to detect a delimiter in a string in PHP?

Question

I am curious if you have a string how would you detect the delimiter?

We know php can split a string up with explode() which requires a delimiter parameter.

But what about a method to detect the delimiter before sending it to explode function?

Right now I am just outputting the string to the user and they enter the delimiter. That's fine -- but I am looking for the application to pattern recognize for me.

Should I look to regular expressions for this type of pattern recognition in a string?

EDIT: I have failed to initially specify that there is a likely expected set of delimiters. Any delimiter that is probably used in a CSV. So technically anyone could use any character to delimit a CSV file but it is more probable to use one of the following characters: comma, semicolon, vertical bar and a space.

EDIT 2: Here is the workable solution I came up with for a "determined delimiter".

$get_images = "86236058.jpg 86236134.jpg 86236134.jpg";

    //Detection of delimiter of image filenames.
        $probable_delimiters = array(",", " ", "|", ";");

        $delimiter_count_array = array(); 

        foreach ($probable_delimiters as $probable_delimiter) {

            $probable_delimiter_count = substr_count($get_images, $probable_delimiter);
            $delimiter_count_array[$probable_delimiter] = $probable_delimiter_count;

        }

        $max_value = max($delimiter_count_array);
        $determined_delimiter_array = array_keys($delimiter_count_array, max($delimiter_count_array));

        while( $element = each( $determined_delimiter_array ) ){
        $determined_delimiter_count = $element['key'];
        $determined_delimiter = $element['value'];
        }

        $images = explode("{$determined_delimiter}", $get_images);

Answer 1

Determine which delimiters you consider probable (like ,, ; and |) and for each search how often they occur in the string (substr_count). Then choose the one with most occurrences as the delimiter and explode.

Even though that might not be fail-safe it should work in most cases ;)