C# regex to convert camelCase to Sentence case

Question

In my example var key = new CultureInfo("en-GB").TextInfo.(item.Key) produces, 'Camelcase' what regular expression could I add that would produce a space before the second 'c' ?

Examples:

'camelCase' > 'Camel case'

'itIsTimeToStopNow' > 'It is time to stop now'

Answer 1

One of the ways how you can do it.

string input = "itIsTimeToStopNow";
string output = Regex.Replace(input, @"\p{Lu}", m => " " + m.Value.ToLowerInvariant());
output = char.ToUpperInvariant(output[0]) + output.Substring(1);

Answer 2

One way is to replace capital letters with space capital letters then make the first character uppercase:

var input = "itIsTimeToStopNow";

// add spaces, lower case and turn into a char array so we 
// can manipulate individual characters
var spaced = Regex.Replace(input, @"[A-Z]", " $0").ToLower.ToCharArray();

// spaced = { 'i', 't', ' ', 'i', 's', ' ', ... }

// replace first character with its uppercase equivalent
spaced[0] = spaced[0].ToString().ToUpper()[0];

// spaced = { 'I', 't', ' ', 'i', 's', ' ', ... }

// combine the char[] back into a string
var result = String.Concat(spaced);

// result = "It is time to stop now"