Match substring surrounded by known prefix and suffix using regex in c#
Add prefix and/or suffix to substring using regex match using c# Example 1: string strline = "This is 123 test string"; strline = Regex.Replace(strline, @"([\d])", "[$1]"); Console.WriteLine(strline); Out Put: is [1][2][3] test string Example 2: string strline = "That's first [good] mark_test"; strline = Regex.Replace(strline, @"([^A-Za-z0-9 ])", "\\$1"); Console.WriteLine(strline); Out Put: That\'s first \[good\] mark\_test Example 3: string strline = "Hello [123] Frinds"; strline = Regex.Replace(strline, @"([^\[])(\[\d+\])(.*)", "$1xxxxxxxxx $2 xxxxxxxxx$3"); Console.WriteLine(strline); Out Put: Hello xxxxxxxxx [123] xxxxxxxxx Frinds Note: In this example $1, $2, $3 means respective value of match group