Returning the existence of a key in a dict by searching key substring

Question

I have a dictionary of string people (key) and string addresses (value). I want to have an if statement that returns true if any key in my dictionary contains the substring

Answer 1

Everyone has already pointed out the obvious (and correct) Any method, but one note: Using String.Contains as the predicate will only return true if the case of the substring is also correct. To do a case-insensitive search, use a simple Regex:

dict.Keys.Any(x => Regex.IsMatch(x, "(?i)anders"));

Or use IndexOf with the StringComparison argument (as in Case insensitive 'Contains(string)'):

dict.Keys.Any(x => x.IndexOf("anders", StringComparison.InvariantCultureIgnoreCase) >= 0);