ios - 谓词的核心数据提取请求错误

Question

需要

我必须找到 rec_name 是“Apple 256GB Macbook”& isActive == true 的记录。

获取请求

fetchRequest.predicate = NSPredicate(format: "rec_name LIKE[cd] *%@* AND rec_name LIKE[cd] *%@* AND isActive = %@","apple","macbook",true)

错误

Unable to parse the format string "rec_name LIKE[cd] *%@* AND rec_name LIKE[cd] *%@* AND isActive = %@"

谢谢

Answer 1

问题是因为*%@*这里%@之间的*没有被替换成字符串参数所以 NSPredicate 无法使您的查询 LIKE *apple* 和 LIKE *macbook* 您需要做的是使用通配符和 Like 创建一个搜索字符串只需使用 %@，@Vadian 建议使用数字代替 Bool。

let searchkeyword1 = "apple"
let searchkeyword2 = "macbook"

//Make search string wildcards charaters
let searchString1 = "*\(searchkeyword1)*"
let searchString2 = "*\(searchkeyword2)*"

fetchRequest.predicate = NSPredicate(format: "rec_name LIKE[cd] %@ AND rec_name LIKE[cd] %@ AND isActive = %@", searchString1,searchString2, true as NSNumber)

这里还有一个更好的选择，你可以使用 CONTAINS 而无需使用通配符。

fetchRequest.predicate = NSPredicate(format: "rec_name CONTAINS[cd] %@ AND rec_name CONTAINS[cd] %@ AND isActive = %@", "apple","macbook", true as NSNumber)

如果你想找到所有以 apple 开头以 macbook 结尾的记录，你可以再做一件事，然后你可以简单地使用 BEGINSWITH 和 ENDSWITH

fetchRequest.predicate = NSPredicate(format: "rec_name BEGINSWITH[cd] %@ AND rec_name ENDSWITH[cd] %@ AND isActive = %@", "apple","macbook", true as NSNumber)