如何过滤多个变量，其中之一是Swift中的Date？

Question

Realm version -> 2.10

Swift version > 3

var uuid: String
var resolutionID: Int
var dateFrom: Date

...

I checked that the variables are not null. I tried:

realm.objects(DeviceDataRealm.self).filter("device.uuid == '\(uuid)' AND resolution.idResolution == \(resolutionID) AND time > \(dateFrom)")

It does not work...

I tried with NSPredicate too:

let predicate = NSPredicate(format: "device.uuid = %@ AND resolution.idResolution = %@ AND time > %@", uuid, resolutionID, dateFrom as CVarArg)
realm.objects(DeviceDataRealm.self).filter(predicate)

It works only without the Date variable:

realm.objects(DeviceDataRealm.self).filter("device.uuid == '\(uuid)' AND resolution.idResolution == \(resolutionID))

Any idea??

Thanks.

Answer 1

When using predicates, you shouldn't embed the variable values inside the predicates, since that can often lead to problems, but should use the %@ inside the predicate and write the variable names after the predicate.

However,the issue was with mixing up the comparison operators. I think you misunderstood how variables should be embedded to predicates. Looking at the extract of your Realm model class definition, there's no property named time , only dateFrom . Class properties should either be inside the predicate as normal Strings or referred to using the %K syntax, while the variable names you want to filter for should be referenced to using the %@ syntax.

Below code was tested in a Realm playground and outputs the expected result.

class DeviceDataRealm: Object {
    var uuid: String = ""
    var resolutionID: Int = 0
    var dateFrom: Date = Date()
}

let deviceData = [DeviceDataRealm(value: ["dateFrom":Date.distantPast,"resolutionID":1]),DeviceDataRealm(value: ["dateFrom":Date.distantFuture,"resolutionID":2])]
try! realm.write {
    realm.add(deviceData)
}

let searchUuid = "",searchResolutionID = 2, searchDateFrom = Date()
print(realm.objects(DeviceDataRealm.self).filter("uuid = %@ AND resolutionID = %@ AND dateFrom > %@", searchUuid, searchResolutionID, searchDateFrom))

Output:

Results <0x7fcc2c642280> ( [0] DeviceDataRealm { uuid = ; resolutionID = 2; dateFrom = 4001-01-01 00:00:00 +0000; } )