Given a dictionary that defines your replacements:
IDictionary<string, string> map = new Dictionary<string, string>()
{
{"&","__amp"},
{"#","__hsh"},
{"1","5"},
{"5","6"},
};
You can use this both for constructing a Regular Expression, and to form a replacement for each match:
var str = "a1asda&fj#ahdk5adfls";
var regex = new Regex(String.Join("|",map.Keys));
var newStr = regex.Replace(str, m => map[m.Value]);
// newStr = a5asda__ampfj__hshahdk6adfls
Live example: http://rextester.com/rundotnet?code=ADDN57626
This uses a Regex.Replace
overload which allows you to specify a lambda expression for the replacement.
It has been pointed out in the comments that a find pattern which has regex syntax in it will not work as expected. This could be overcome by using Regex.Escape
and a minor change to the code above:
var str = "a1asda&fj#ahdk5adfls";
var regex = new Regex(String.Join("|",map.Keys.Select(k => Regex.Escape(k))));
var newStr = regex.Replace(str, m => map[m.Value]);
// newStr = a5asda__ampfj__hshahdk6adfls