Check If String Contains All “?”

Question

How can I check if a string contains all question marks? Like this:

string input = \"????????\";

Answer 1

Not very readable... But a regular expression is another way to do it (and it's fast):

// Looking for a string composed only by one or more "?":
bool allQuestionMarks = Regex.IsMatch(input, "^\?+$");

Answer 2

You can also try this:

private bool CheckIfStringContainsOnlyQuestionMark(string value)
{
    return !value.Where(a => a != '?').Select(a => true).FirstOrDefault();
}