Removing all whitespace lines from a multi-line string efficiently

Question

In C# what\'s the best way to remove blank lines i.e., lines that contain only whitespace from a string? I\'m happy to use a Regex if that\'s the best solution.

EDIT

Answer 1

not good. I would use this one using JSON.net:

var o = JsonConvert.DeserializeObject(prettyJson);
new minifiedJson = JsonConvert.SerializeObject(o, Formatting.None);