NSPredicate：无法解析格式字符串

Question

我写了下面的谓词，但它使应用程序崩溃，原因是 'Unable to parse the format string "(rootActivityId IN 12,13 AND (activityType == 3 OR activityType == 2)) OR (activityId IN 12,13 AND (activityType == 3 OR activityType == 2))"'

let activityTypeClause = "(activityType == \(NSNumber(integer: ActivityType.TypeTwo)) OR activityType == \(NSNumber(integer: ActivityType.TypeOne)))"
fetchRequest.predicate = NSPredicate(format: "(rootActivityId IN \(activityIds) AND \(activityTypeClause)) OR (activityId IN \(activityIds) AND \(activityTypeClause))")

// activityIds contains coma separated string

我不知道我哪里做错了。

Answer 1

来自 IN 的文档：

Equivalent to an SQL IN operation, the left-hand side must appear in the collection specified by the right-hand side. For example, name IN { 'Ben', 'Melissa', 'Nick' }. The collection may be an array, a set, or a dictionary—in the case of a dictionary, its values are used.

这表明逗号分隔的字符串实际上应该是一个集合对象。我不清楚是否需要 NS 风格的 Swift 集合。

不评论它是否作为谓词起作用，但以下不会给我解析错误：

let rootActivityId = "12"
let activityIds = ["12", "13"]

let pred = NSPredicate(format: "rootActivityId IN %@", argumentArray: [activityIds])

NSPredicate：无法解析格式字符串

NSPredicate: Unable to parse the format string

core-data

nspredicate

swift