I need to validate that the user entered text in the format:
####-#####-####-###
Can I do this using Regex.Match?
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1 Answer
I would do something like this:
private static readonly Regex _validator =
new Regex(@"^\d{4}-\d{5}-\d{4}-\d{3}$", RegexOptions.Compiled);
private static bool ValidateInput(string input)
{
input = (input ?? string.Empty);
if (input.Length != 19)
{
return false;
}
return _validator.IsMatch(input);
}
9 Comments
Liviu Mandras
Isn't that only for numbers? It is true that the question does not specify exactly what "text" is.
ChaosPandion
@Liviu - I usually interpret # as a numeric placeholder.
dstarh
why go through the trouble of checking the length and and having multiple returns, is the precompiled regex operation so expensive that it's not worth doing? I would just let it fail the regex and make the method simpler. I do however like that you are using \d instead of [0-9]
ChaosPandion
@dstarh - I don't consider checking the length to be much trouble. It is such an easy way to validate the input. In a high throughput process it can make a difference in performance as well. (Not much I admit.)
tchrist
Should those literal
- characters, code point 45 HYPHEN-MINUS, be better written as \p{Pd} for any sort of dash punctuation? And if you wanted them to be all of the same sort, you could write ^\d{4}(\p{Pd})\d{5}\1\d{4}\p{Pd}\1\d{3}$. |