Sometimes, you end up with code that looks like this:
if (!c.Equals('.') && !c.Equals('_') && !c.Equals(' ') && !c.Equals('-'))
{ /* whatever */ }
Obviously, this works, but it’s not very obvious, and it can get pretty unwieldy (imagine if those characters were all enums…). Wouldn’t it be nice to have a straightforward way to say “if the value is in this set of values…”, like you do with the SQL keyword IN?
Well, now you have one.
public static bool In<T>(this T itemToLookFor, params T[] itemsToLookIn)
{
return itemsToLookIn.Contains(itemToLookFor);
}
Stick this handy extension method in a static class in your project, and then you’ll be able to rewrite the first code as:
if (!c.In('.', '_', ' ', '-')) { /* whatever */ }
“But wait!” you cry. “Couldn’t you just write this:”
if (!new[] { '.', '_', ' ', '-' }.Contains(c)) { /* whatever */ }
Yes, and that would function just as well. But, consider how the code reads. Using In(), the code reads like you would say it: “If not ‘c’ in ‘.’, ‘_’…”. In the second example, the order of the variables is reversed, and the variable we’re looking at gets lost in the Contains call. So, I find it much cleaner to use In() when possible.
Geoffrey Lehr Software Engineer
In addition to programming, this multitalented (and handsomely modest!) developer enjoys playing & composing music, reading SF and playing video games.