正则表达式匹配单词的开头但替换整个单词

Question

I want to search for all words that start with a pattern and then replace the whole word with another text. I see that we can do a whole word match only and replace it but did not find a way of matching the start and replacing the whole word.

string input = "My name is ABCDEFG and not ABCDQWER"
string pattern = @"\bABCD";
string replace = "text";
string result = Regex.Replace(input, pattern, replace);
Console.WriteLine(result);

Above code obviously won't work for me because we are replacing only the text that matched. If I run the code on the above text, I get "My name is textEFG and not textQWER". What I need is "My name is text and not text". The only way I see if doing a loop on all the words but trying to avoid that and see if we have a regex way.

Answer 1

You may try matching on the pattern \\bABCD\\w* , which would match any word which starts with ABCD , which however may be longer than that.

string input = "My name is ABCDEFG and not ABCDQWER";
string pattern = @"\bABCD\w*";
string replace = "text";
string result = Regex.Replace(input, pattern, replace);
Console.WriteLine(result);  // My name is text and not text