How to write a BOOL predicate in Core Data?

Question

I have an attribute of type BOOL and I want to perform a search for all managed objects where this attribute is YES.

For string attributes it is straightforward. I create a predicate like this:

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"userName = %@", userName];

But how do I do this, if I have a bool attribute called selected and I want to make a predicate for this? Could I just do something like this?

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"selected = %@", yesNumber];

Or do I need other format specifiers and just pass YES?

albertamg · Accepted Answer · 2011-05-29T17:24:55.220

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From Predicate Programming Guide:

You specify and test for equality of Boolean values as illustrated in the following examples:

NSPredicate *newPredicate = [NSPredicate predicateWithFormat:@"anAttribute == %@", [NSNumber numberWithBool:aBool]];
NSPredicate *testForTrue = [NSPredicate predicateWithFormat:@"anAttribute == YES"];

You can also check out the Predicate Format String Syntax.

edited May 29 '11 at 17:24

answered May 29 '11 at 17:19

albertamg

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@inorganik I've read a similar claim [here](http://stackoverflow.com/a/22043435/375300). I don't know what is the reason for this but afaik it *should* work and it does for me. – albertamg May 05 '15 at 14:40
@inorganik I also tried it and it worked ("it does for me"). I don't know what you tried. I'm curious about it. If you want, share a link to a test case so I can try the exact same code. – albertamg May 05 '15 at 21:22
I retested and it worked... so I was wrong. Something else must have caused my case to fail. Either way +1 on your answer – inorganik May 05 '15 at 21:27
@inorganik oh I see. If you find out what caused your case to fail i would love to know. Thanks for the +1! :) – albertamg May 05 '15 at 21:31

Viktor Kucera · Answer 2 · 2017-09-15T05:19:07.877

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Swift 4.0

let predicate = NSPredicate(format: "boolAttribute == %@", NSNumber(value: true))

edited Sep 15 '17 at 05:19

answered Jan 06 '16 at 11:06

Viktor Kucera

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Is there any way to fetch all objects for bool is equal to nil ?? Or does it always have to be either true or false ?? – Apoorv Mote Jul 17 '16 at 18:07
@ApoorvMote, as of Xcode 9.4, Swift 4, yes: if you use a regular Bool value in the predicate, items with `nil` attribute values will be found. For example, set an attribute's value to `nil` (we'll say you called it `boolAttribute` as shown in this answer). Then, create your predicate: `let predicate = NSPredicate(format: "boolAttribute == %@", boolValue)`. *Note: `boolValue` should equal `true` or `false`, NOT `NSNumber(value: boolValue)`.* The resulting predicate will be: `boolAttribute == nil`. That predicate *will* return any objects where `boolAttribute` is `nil`. Might not work forever... – leanne Jul 10 '18 at 20:10
This is works. You can simply use "boolAttribute == 1" format also. – Zoltan Vinkler Nov 20 '18 at 21:14

score 44 · Answer 3 · edited Aug 23 '19 at 18:48

44

Don't convert to NSNumber, nor use double "=="

More appropriate for Swift >= 4:

NSPredicate(format: "boolAttribute = %d", true)

Note: "true" in this example is a Bool (a Struct)

edited Aug 23 '19 at 18:48

mahan

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answered Apr 01 '19 at 08:50

alegelos

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should be new accepted answer. it's 2020 for pete's sake – RyanM Feb 06 '20 at 21:36
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This doesn't work for me when using an `NSPredicate` with Core Data. Only the `NSNumber` version works (@Viktor's answer). – Clifton Labrum Feb 16 '21 at 01:38
This is not worked for me as well. – Ramakrishna Mar 07 '21 at 05:32

score 18 · Answer 4 · answered Mar 21 '17 at 16:41

Swift 3

let predicate = NSPredicate(format: "boolAttribute == %@", NSNumber(value: true))

In Swift 3 you should use NSNumber(value: true).

Using NSNumber(booleanLiteral: true) and in general any literal initialiser directly is discouraged and for example SwiftLint (v. 0.16.1) will generate warning for usage ExpressibleBy...Literal initialiser directly:

Compiler Protocol Init Violation: The initializers declared in compiler protocols such as ExpressibleByArrayLiteral shouldn't be called directly. (compiler_protocol_init)

Alternatively: `NSPredicate(format: "boolAttribute == %@", true as NSNumber)` — Martin R, May 15 '17 at 07:47

SoftDesigner · Answer 5 · 2018-04-26T07:50:49.667

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Swift 4

request.predicate = NSPredicate(format: "boolAttribute == %@", NSNumber(value: true))

Swift 3

request.predicate = NSPredicate(format: "field = %@", value as CVarArg)

edited Apr 26 '18 at 07:50

answered Dec 08 '17 at 20:25

SoftDesigner

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This causes a crash with Xcode 9.3 and Swift 4.1. Use [this method](https://stackoverflow.com/a/34631602/3151675) instead. – Tamás Sengel Apr 04 '18 at 14:33

score 2 · Answer 6 · answered Sep 24 '16 at 14:19

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Swift 3.0 has made a slight change to this:

let predicate = NSPredicate(format: "boolAttribute == %@", NSNumber(booleanLiteral: true))

answered Sep 24 '16 at 14:19

Mario Hendricks

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How to write a BOOL predicate in Core Data?

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