使用自定义范围

Question

我想证明我的数组

let actualSigns = ["Aa", "Bb", "Cc"]

...等于这一个中的一个数组...

var validSigns = [[String]]()
validSigns.append(["Aa", "Bb", "Cc", "Dd"]) // want to match this
validSigns.append(["Aa", "Bb", "Cc", "Xy"]) // ... and this
validSigns.append(["Ee", "Ff", "Gg", "Hh"])

...仅比较actualSigns的对象数量。

所以在这种情况下，我希望匹配validSigns中的第一个和第二个数组，因为前三个值等于actualSigns。

我尝试过滤它

let range = Range(start: actualSigns.count, end: actualSigns.count+1)
let match = validSigns.filter{ $0.removeRange(range) == actualSigns }

但是编译器说'$0 is a let constant'。我该如何解决这个问题？

Answer 1

我不确定我是否理解正确但您不需要使用范围来获得匹配：

// My original answer
let match = validSigns.filter { !zip($0, actualSigns).contains { $0.0 != $0.1 } }

// Based on Price Ringo's answer
let match = validSigns.filter { $0.startsWith(actualSigns) }

输出：

[["Aa", "Bb", "Cc", "Dd"], ["Aa", "Bb", "Cc", "Xy"]]

Answer 2

在要测试的阵列上使用startsWith。

let match = validSigns.filter{$0.startsWith(actualSigns)}

Answer 3

您可以通过执行以下操作来修复错误：

let match = validSigns.filter{ var input = $0; input.removeRange(range); return input == actualSigns }

其他一些方法，只是为了完整性：

import Foundation

let actualSigns = ["Aa", "Bb", "Cc"]
var validSigns = [
  ["Aa", "Bb", "Cc", "Dd"],
  ["Aa", "Bb", "Cc", "Xy"],
  ["Ee", "Ff", "Gg", "Hh"],
  ["Ee", "Aa", "Bb", "Cc"]] // Added another case, to test when the matching array is not at the start

let matches = validSigns.filter { $0.joinWithSeparator("").containsString(actualSigns.joinWithSeparator("")) }
// => [["Aa", "Bb", "Cc", "Dd"], ["Aa", "Bb", "Cc", "Xy"], ["Ee", "Aa", "Bb", "Cc"]]

let matches2 = validSigns.filter { Set($0).intersect(Set(actualSigns)).count == actualSigns.count }
// => [["Aa", "Bb", "Cc", "Dd"], ["Aa", "Bb", "Cc", "Xy"], ["Ee", "Aa", "Bb", "Cc"]]