Question

I want in a good performance way (I hope) replace a named parameter in my string to a named parameter from code, example, my string:

'Hi {name}, do you like milk?' 

How could I replace the {name} by code, Regular expressions? To expensive? Which way do you recommend?

How do they in example NHibernates HQL to replace :my_param to the user defined value? Or in ASP.NET (MVC) Routing that I like better, ‘{controller}/{action}’, new { controller = ‘Hello’, … }?

Answer 1

Have you confirmed that regular expressions are too expensive?

The cost of regular expressions is greatly exaggerated. For such a simple pattern performance will be quite good, probably only slightly less good than direct search-and-replace, in fact. Also, have you experimented with the Compiled flag when constructing the regular expression?

That said, can’t you just use the simplest way, i.e. Replace?

string varname = 'name'; string pattern = '{' + varname + '}'; Console.WriteLine('Hi {name}'.Replace(pattern, 'Mike'));