Question

I need help in removing letters but not words from an incoming data string. Like the following,

String A = "1 2 3A 4 5C 6 ABCD EFGH 7 8D 9";

to

String A = "1 2 3 4 5 6 ABCD EFGH 7 8 9";

Answer 1

You need to match a letter and ensure that there is no letter before and after. So match

(?<!\p{L})\p{L}(?!\p{L})

and replace with an empty string.

• Look around assertions on regular-expresssion.info

• Unicode properties on regular-expresssion.info

In C#:

string s = "1 2 3A 4 5C 6 ABCD EFGH 7 8D 9";
string result = Regex.Replace(s, @"(?<!\p{L}) # Negative lookbehind assertion to ensure not a letter before
                                   \p{L}      # Unicode property, matches a letter in any language
                                   (?!\p{L})  # Negative lookahead assertion to ensure not a letter following
                                  ", String.Empty, RegexOptions.IgnorePatternWhitespace);