arrays - 使用 core-data 从初始化器中的字符串数组中减去 Stings？

Question

我需要使用存储的数组来改变库。这有效:

var library = ["Monday", "Tuesday","wednesday", "Thursday"]

var libraryOff = ["Monday","wednesday"]

library = Array(Set(library).subtracting(libraryOff))

print(library) //=>["Tuesday", "Thursday"]

但是，我需要它使用类似的东西来工作，

var library = ["Monday", "Tuesday","wednesday", "Thursday"]

var libraryOff = [newLibrary]

library = Array(Set(library).subtracting(libraryOff))

newLibrary 是 coreData，打印时读取为“星期一，星期三”，

Answer 1

数组-设置-数组舞蹈很丑陋，有一种更有效的方法

var library = ["Monday", "Tuesday","wednesday", "Thursday"]
let libraryOff = ["Monday","wednesday"] // Why is wednesday lowercased?

library.removeAll{ libraryOff.contains($0) }

要使用逗号分隔的字符串，您必须拆分字符串并删除可能的前导和尾随空白字符

var library = ["Monday", "Tuesday","wednesday", "Thursday"]
let libraryOff =  "Monday, wednesday"
let trimmedLibraryOff = libraryOff.split(separator: ",").map{$0.trimmingCharacters(in: .whitespaces)}

library.removeAll{ trimmedLibraryOff.contains($0) }