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