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iOS Swift Filter Array using NSPredicate crashing on run time

I have a cell Model

struct BeerCellModel: Hashable

var beer: Beer

static func == (lhs: BeerCellModel, rhs: BeerCellModel) -> Bool
return lhs.beer.id == rhs.beer.id


var hashValue: Int
return self.beer.id




AND

public struct Beer
public var abv: String
public var ibu: String
public var id: Int
public var name: String
public var style: String
public var ounces: Int



Now i have a array name 'items = [BeerCellModel]' of above cell model and i'm filtering array with param style

style

let value = ["tuborg", "budwiser", "bira"]
let query = value.map "SELF.beer.style CONTAINS[cd] ($0)" .joined(separator: " || ")
let predicate = NSPredicate(format: query)
let results = self.items.filter predicate.evaluate(with: $0)


But i'm getting run time crash

2018-08-08 00:38:01.787170+0530 BeerCrafts[3388:401950] ***
Terminating app due to uncaught exception 'NSUnknownKeyException',
reason: '[<_SwiftValue 0x60400064dce0> valueForUndefinedKey:]: this
class is not key value coding-compliant for the key beer.'

What is wrong in array or predicate?

Update: Adding JSON response of Beer

Beer


"abv": "0.08",
"ibu": "35",
"id": 11,
"name": "Monks Blood",
"style": "Belgian Dark Ale",
"ounces": 12
,

"abv": "0.07",
"ibu": "65",
"id": 10,
"name": "Brew Free! or Die IPA",
"style": "American IPA",
"ounces": 12
,

"abv": "0.04",
"ibu": "17",
"id": 9,
"name": "Hell or High Watermelon Wheat",
"style": "Fruit / Vegetable Beer",
"ounces": 12



BeerCellModel

BeerCellModel

items

NSPredicate(format: "beer.style IN %@", value)

3 Answers
3

At this point, there is no need to deal with NSPredicate, the filter method is handy enough for your case! all you should do is:

NSPredicate

filter

let filtered = items.filter value.contains($0.beer.style)


The filtered is array of BeerCellModel which should contains the objects that their beer.style is one of the value array elements.

filtered

BeerCellModel

beer.style

value

You can try

let value = ["tuborg", "budwiser", "bira"]
let query = value.map "self CONTAINS[cd] '($0)'" .joined(separator: " || ")
let predicate = NSPredicate(format: query)
let results = self.items.filter predicate.evaluate(with: $0.beer.style)


Looks like you're trying to map an array of Strings, not an array of BeerCellModel structs.

String

BeerCellModel

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