NSPredicate, NsNumber numberWithFloat:0.0 (iPhone)

Question

hi i have Core Data database with numerical attributes. they are NSNumbers. Default value is 0.0 but when i try to do some NSPredicated fetch, i get "'NSInvalidArgumentException', reason: 'Invalid predicate: nil RHS'" just because attribute value is 0.0

The predicate is created with:

[NSPredicate predicateWithFormat:@"(startValue => %@) AND (endValue <= %@) AND (someId == %@)",startNSNumber,endNSNumber, idString]

how can i solve this problem ?

predicate:[NSPredicate predicateWithFormat:@"(startValue => %@) AND (endValue < %@) AND (someId == %@)",startNSNumber,endNSNumber, idString] — Greg, Sep 29 '10 at 16:39
maybe we need to have a bigger view of the problem to help, can you provide more lines of code: especially where startNSNumber, endNSNumber and iString come from? — Mick F, May 22 '12 at 10:10

score 5 · Answer 1 · edited Sep 28 '11 at 20:11

5

You're adding the floats as objects, not as floats? Try this :

[NSPredicate predicateWithFormat:@"(startValue => %f) AND (endValue <= %f) AND (someId == %@)",startNSNumber,endNSNumber, idString];

edited Sep 28 '11 at 20:11

Alexsander Akers

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answered Sep 29 '10 at 16:40

deanWombourne

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`%f` is used for a `float` primitive. `NSNumber` is an object (which means that `%@` is the correct substitution for it). – Dave DeLong Sep 29 '10 at 16:43
Blast, I misread the question and thought he was adding floats :( – deanWombourne Sep 29 '10 at 16:43

score 2 · Answer 2 · answered Sep 29 '10 at 19:10

2

I strongly believe one of your variables is nil or was autoreleased...

try this:

NSNumber *num1 = [NSNumber numberWithFloat:2.0];
NSNumber *num2 = [NSNumber numberWithFloat:3.0];
NSString *str = @"Test";
[NSPredicate predicateWithFormat:@"(startValue => %@) AND (endValue <= %@) AND (someId == %@)", num1, num2, str];

If this succeeds that the problem is with your variables.

If you expect either num1 or num2 to be nil sometimes, then you could rewrite the predicate as:

[NSPredicate predicateWithFormat:@"(startValue => %@) AND (endValue <= %@) AND (someId == %@)", num1 ? num1 : [NSNumber numberWithFloat:0.0], num2 ? num2 : [NSNumber numberWithFloat:0.0], idString];

answered Sep 29 '10 at 19:10

Nick

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yeah -.-' my problem is when num1 or num2 is [NSNumber numberWithFloat:0.0] but this value is possible and necessary, but NSPredicate doesn't like it. throws exceptions. why?! – Greg Sep 29 '10 at 20:19
that is quite surprising, are you sure the variable is not `nil`? I've run a test code with a break point and `[NSNumber numberWithFloat:0.0]` generates a proper `NSNumber` object... – Nick Sep 29 '10 at 21:08

score 1 · Answer 3 · answered Sep 29 '10 at 16:41

1

Well, given the predicate you provided, the easy answer is:

Either startNSNumber, endNSNumber or idString is nil. If you want to compare something against nil in an NSPredicate, you need to substitute in [NSNull null], not nil.

answered Sep 29 '10 at 16:41

Dave DeLong

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so if (startNSNumber) { [NSPredicate predicateWithFormat:@"(startValue => %@), startNSNumber] } else { [NSPredicate predicateWithFormat:@"(startValue => %@), [NSNull null] } ?? will it be right ?! – Greg Sep 29 '10 at 16:47

score 0 · Answer 4 · answered Oct 05 '13 at 13:06

IN NSpredicate use string value as float the Dictionary key.floatValue and easily use.

[NSPredicate predicateWithFormat:@"(startValue.floatValue => %f) AND (endValue.floatValue <= %f) AND (someId == %@)",startNSNumber,endNSNumber, idString]

I thing this post useful.

NSPredicate, NsNumber numberWithFloat:0.0 (iPhone)

4 Answers4