Quicker if-statement: if `variable` is “value” or “value”

Question

How can you compare against multiple possibilities in one argument?

Example:

if ((integer == 2) || (integer == 5))

if ((string == \"hello\") || (str         


        

Answer 1

Actually, you can check if NSSet contains some object. This won't work with int, as it's not an object, but will work with NSString.

I believe it could be written like this:

if ( [[NSSet setWithObjects:@"hello", @"dolly", nil] containsObject:string] )

So, if you want to compare ints, you should wrap them with NSNumber.

This won't save a lot of code if you are not comparing tens of objects, but this looks pretty similar to what you want to get :)

UPDATE:

Or another way (quite similar to the answer from John Calsbeek, but works for multiple arguments):

@implementation NSObject (IsEqualMultiple)

- (BOOL)isEqualToOneOfObjects:(id)firstObject, ... {
    id eachObject;
    va_list argumentList;

    if (firstObject) {
        if ( [self isEqual:firstObject] ) return YES;

        va_start(argumentList, firstObject);

        while (eachObject = va_arg(argumentList, id))
            if ( [self isEqual:eachObject] ) return YES;
        va_end(argumentList);
    }

    return NO;
}

@end

Usage:

if ( [string isEqualToOneOfObjects:@"hello", @"dolly", @"this", @"is", @"Louis", nil] )