Convert regex pattern from php to C#

Asked Aug 31 '18 at 16:42

Active Aug 31 '18 at 16:59

Viewed 42 times

I have this regex pattern (written for PHP):

(?:"(?:\\"|[^"])*"|)\K(,)

I need to use this in dotnet, but \K is not supported. Is there an alternative I can use to produce the same effect?

Edit:

This regex is part of this method:

private static function fix_json(string $json){
    if(preg_match('/^\[(.+)\]$/s', $json, $matches) > 0){
        $parts = preg_split('/(?:"(?:\\"|[^"])*"|)\K(,)/', $matches[1]); //Splits on commas not inside quotes, ignoring escaped quotes
        foreach($parts as $k => $part){
            $part = trim($part);
            if($part === ""){
                $part = "\"\"";
            }
            $parts[$k] = $part;
        }
        $fixed = "[" . implode(",", $parts) . "]";
        return $fixed;
    }
    return $json;
}

This method fixes a JSON list with empty items. E.g. from [null,,,] to [null,"","",""]. It also should not break with escaped quotation marks inside string values (e.g. [null,"quote \"",]) and also with commas inside (e.g. [null,,"commas,,",])

edited Aug 31 '18 at 16:59

asked Aug 31 '18 at 16:42

Samueljh1

What is the use case? – Wiktor Stribiżew Aug 31 '18 at 16:44
Instead of converting, just edit the question to add what you want the regex to do. And some sample input/output. – Sach Aug 31 '18 at 16:52
@WiktorStribiżew updated. – Samueljh1 Aug 31 '18 at 16:59
@Sach updated it. – Samueljh1 Aug 31 '18 at 16:59
What's the expected output for `[null,"quote \"",]` and `[null,,"commas,,",]`? – Sach Aug 31 '18 at 17:05
Try to use the built-in CSV parser - http://stackoverflow.com/questions/6542996/how-to-split-csv-whose-columns-may-contain/6543418#6543418 – Wiktor Stribiżew Aug 31 '18 at 17:07
@Sach `[null,"quote \"",""]` and `[null,"","commas,,",""]` but it only needs to work on the text inside of the square brackets, the first part of the method deals with that. – Samueljh1 Aug 31 '18 at 17:37
Please try the solution in the linked thread and update the question with that try. – Wiktor Stribiżew Sep 01 '18 at 08:18
@WiktorStribiżew i'm using dotnetcore, so that library isn't supported. I think the best solution is regex, there must be a solution surely? – Samueljh1 Sep 01 '18 at 10:48
Not sure, try https://ideone.com/UY33Y3 – Wiktor Stribiżew Sep 02 '18 at 22:21
@WiktorStribiżew thank you, that looks great, but it does not seem to fix the last part correctly. In the example you used, the output is `[null,"","\"","",]` rather than `[null,"","\"","",""]`. Is it possible for you to update that? – Samueljh1 Sep 04 '18 at 13:39
@Samueljh1 Try https://ideone.com/3hXiPf – Wiktor Stribiżew Sep 04 '18 at 14:27

Convert regex pattern from php to C#

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