具有多个OR语句的Objective-C IF语句

Question

I was wondering if there was a simpler way to do multiple OR statements as part of a singe IF statement.

Currently I am doing them like this:

            if ((i == 1) || (i == 4) || (i == 7)) {}

Is there a simpler way?

Answer 1

You could use a switch block with fall through.

switch (i)
{
    case 1:
    case 4:
    case 7:
        yourCode;
        break;
}

Answer 2

You can use NSArray 's containsObject: method, like this:

if ([@[@1, @4, @7] containsObject:@(i)]) {
    ...
}

The usefulness of this approach improves with the length of the list: with three items, your solution looks better, but once you cross the limit of about ten numbers, this solution becomes more and more readable:

if ([@[@1, @3, @12, @17, @23, @27, @31, @41, @43, @57] containsObject:@(i)]) {
    ...
}

You can make a named array for the list of expected constants @[@1, @4, @7] to shorten the if , like this:

NSArray *expect = @[@1, @4, @7];
...
if ([expect containsObject:@(i)]) {
    ...
}