Remove white spaces unless within quotes, ignoring escaped quotes

Question

I have a JSON string in which I would like to remove all white spaces that are not within quotes. I searched online and I already found a solution, which is the following:

aidstring = Regex.Replace(aidstring, "\\s+(?=([^\"]*\"[^\"]*\")*[^\"]*$)", "");

However, I am now dealing with a string that contains escaped quotes:

"boolean": "k near/3 \"funds private\""

and the above regular expression solution turns it into:

"boolean":"k near/3 \"fundsprivate\""

Since escaped quotes are treated as normal quotes.

Could anyone post a regex in which escaped quotes are ignored?

Answer 1

I'd suggest using

aidstring = Regex.Replace(aidstring, @"(""[^""\\]*(?:\\.[^""\\]*)*"")|\s+", "$1");

See regex demo

The regex will match all C quoted strings into Capture group 1 and with $1 these strings will be restored in the result, but all whitespaces caught with \s+ will be removed.

Regex explanation:

Alternative 1:

• ("[^"\\]*(?:\\.[^"\\]*)*"):
  • " - a literal "
  • [^"\\]* - zero or more characters other than \ or "
  • (?:\\.[^"\\]*)* - zero or more sequences of...
    • \\. - \ and any character but a newline
    • [^"\\]* - zero or more characters other than \ or "
  • " - a literal "

Alternative 2:

• \s+ - 1 or more whitespace (in .NET, any Unicode whitespace)