如何将 indexPath 数组拆分为单独的 indexPath 数组，每个数组的 indexPath 具有相同的 indexPath.section

Question

最近想根据indexPaths删除单元格，所以函数的入参是[IndexPath]类型，需要根据indexPath.section把[IndexPath]拆分成几个数组，有什么简单的方法可以做到这一点？例如

indexPaths = 
[IndexPath(row: 0, section: 1),
 IndexPath(row: 1, section: 1), 
 IndexPath(row: 2, section: 1), 
 IndexPath(row: 2, section: 0)]

想将其转换为

indexPath1 = 
[IndexPath(row: 0, section: 1),
 IndexPath(row: 1, section: 1), 
 IndexPath(row: 2, section: 1)]

indexPath0 = 
[IndexPath(row: 2, section: 0)]

// maybe get a [Array]
[indexPath0, indexPath1]

Answer 1

一个可能的解决方案是首先构建一个字典，其中键是节号，值是该节中 IndexPath 的数组。

let indexPaths = [
    IndexPath(row: 0, section: 1),
    IndexPath(row: 1, section: 1),
    IndexPath(row: 2, section: 1),
    IndexPath(row: 2, section: 0),
]

let pathDict = Dictionary(grouping: indexPaths) { (path) in
    return path.section
}

然后你可以将这个字典映射到路径数组的数组中。但首先按部分对这些数组进行排序。

let sectionPaths = pathDict.sorted { (arg0, arg1) -> Bool in
    return arg0.key < arg1.key // sort by section
}.map { [=11=].value } // get just the arrays of IndexPath

print(sectionPaths)

输出：

[[[0, 2]], [[1, 0], [1, 1], [1, 2]]]

Answer 2

我们需要一个 HashMap，映射到键上。
我们需要对字典进行排序
我们需要提取字典的值并将它们附加到数组
我们需要return那个数组

var indexPaths = [IndexPath(row: 0, section: 1),
     IndexPath(row: 1, section: 1),
     IndexPath(row: 2, section: 1),
     IndexPath(row: 2, section: 0)
]

extension Array where Element == IndexPath {
    func splitArray() ->  Array<[IndexPath]> {
        var tempDict = [String : [IndexPath]]()
        for element in self {
            let section = element.section
            if tempDict[String(section)] != nil {
                // some element append
                if var array = tempDict[String(section)] {
                    array.append(element)
                    tempDict[String(section)] = array
                }

            } else {
                tempDict[String(section)] = [element]
            }
        }

        // dictionary mayn't have sorted, sort the dictionary 

        tempDict.sorted{ [=10=].key > .key }

        var returnedArray = Array<[IndexPath]>()
        for (key, value) in tempDict {
           returnedArray.append(value)
        }

        return returnedArray
    }
}

print(indexPaths.splitArray())

Answer 3

使用过滤器：

let indexPath0 = indexPaths.filter { [=10=].section == 0 }
let indexPath1 = indexPaths.filter { [=10=].section == 1 }

如何将 indexPath 数组拆分为单独的 indexPath 数组，每个数组的 indexPath 具有相同的 indexPath.section

How to split indexPath array into seperate array of indexPath, each array's indexPath has same indexPath.section

swift

indexpath