Add spacing between lowercase and uppercase?

Question

I would like to add a space when an uppercase character or an underscore is in the string.

How do I do this?

EXAMPLE 1

Input

ThisIsAnInputString

Output (result)

This Is An Input String

EXAMPLE 2

Input

This_Is_An_Input_String

Output (result)

This Is An Input String

Answer 1

You can use a regular expression that matches a lower case character followed by an upper case character, with an optional underscore between:

string output = Regex.Replace(input, "([a-z])_?([A-Z])", "$1 $2");

You might want to use this to handle single character words also:

string output = Regex.Replace(input, "(?<!^)_?([A-Z])", " $1");

Answer 2

Underscores:

string inputString = "This_Is_An_Input_String";
string resultString = inputString.Replace('_', ' ');

Capitals:

string inputString = "ThisIsAnInputString";
//this will put a space before all capitals that are preceded by a lowercase character
string resultString = Regex.Replace(inputString, @"([a-z])([A-Z])", "$1 $2");