NSArray containsObject: a faster alternative?

Question

I did a few runs in my iOS app with tools, and I saw that 90% of the main thread load at startup (about 1000 ms) was caused by containsObject: calls. This is on the main topic, and I do not think it is cool.

Is there a faster alternative to this method? Algorithm or other method?

Any suggestions?

ADDITIONAL INFORMATION:

• I looked at my code again. I realized that I really do not need to know the order of the objects only if the object is part of this set. This means that NSSet will do everything perfectly (and I think it’s faster).

• Number of objects - in this set there can be 1000+ objects.

Answer 1

If you use NEEDS to use an array, skip a little lower

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Alternatives

Other options may include:

• Using NSDictionary , which uses key-> value pairs that (I expect) will have O (1) reading complexity due to the extra key storage space

• If you do not use duplicates and the order is not important, using NSSet will offer a higher degree of reading (I do not know what complexity will be, documents will probably be)

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Using array

If you save the array, you can search in O(log n) time instead of O(n) , since you can use binary search.

Caveat Lector : it was written into memory

 -(void) /*adding*/ { int proposedIndex = 0; proposedIndex = [array indexOfObject:node inSortedRange:NSMakeRange(0, array.count) options:NSBinarySearchingInsertionIndex usingComparator: ^ NSComparisonResult(id obj1, id obj2) { if (obj1.valueToCompare < obj2.valueToCompare) return NSOrderedAscending; if (obj1.valueToCompare > obj2.valueToCompare) return NSOrderedDescending; else return NSOrderedSame; }]; [array insertObject:node atIndex:proposedIndex]; } -(id) /* Getting */ { int location = [array indexOfObject:node inSortedRange:NSMakeRange(0, array.count) options:NSBinarySearchingFirstEqual usingComparator: ^ NSComparisonResult(id obj1, id obj2) { if (obj1.valueToCompare < obj2.valueToCompare) return NSOrderedAscending; if (obj1.valueToCompare > obj2.valueToCompare) return NSOrderedDescending; else return NSOrderedSame; }]; if (location == NSNotFound) return nil; return [array objectAtIndex:location]; } 

Answer 2

You can use NSSet containsObject faster than NSArray