arrays - 数组包含一个完整的子数组

Question

在 Swift 中，我如何检查一个数组是否完整地包含给定的子数组？例如，是否有一个像这样工作的 contains 函数:

let mainArray = ["hello", "world", "it's", "a", "beautiful", "day"]
contains(mainArray, ["world", "it's"])   // would return true
contains(mainArray, ["world", "it"])   // would return false
contains(mainArray, ["world", "a"])   // would return false - not adjacent in mainArray

Answer 1

你可以用更高级的函数来做，像这样:

func indexOf(data:[String], _ part:[String]) -> Int? {
    // This is to prevent construction of a range from zero to negative
    if part.count > data.count {
        return nil
    }

    // The index of the match could not exceed data.count-part.count
    return (0...data.count-part.count).indexOf {ind in
        // Construct a sub-array from current index,
        // and compare its content to what we are looking for.
        [String](data[ind..<ind+part.count]) == part
    }
}

此函数返回第一个匹配项的索引(如果有)，否则返回nil。

您可以按如下方式使用它:

let mainArray = ["hello", "world", "it's", "a", "beautiful", "day"]
if let index = indexOf(mainArray, ["world", "it's"]) {
    print("Found match at \(index)")
} else {
    print("No match")
}

作为通用数组的扩展进行编辑...

这现在可以用于 Equatable 类型的任何同类数组。

extension Array where Element : Equatable {
    func indexOfContiguous(subArray:[Element]) -> Int? {

        // This is to prevent construction of a range from zero to negative
        if subArray.count > self.count {
            return nil
        }

        // The index of the match could not exceed data.count-part.count
        return (0...self.count-subArray.count).indexOf { ind in
            // Construct a sub-array from current index,
            // and compare its content to what we are looking for.
            [Element](self[ind..<ind+subArray.count]) == subArray
        }
    }
}