swift - 如何在 Swift 中过滤字典数组

Question

我选择使用字典对象的可变数组来填充 NSTableview，其中字典键是列标识符，值是列值。我像这样填充数组:

var compArray: NSMutableArray = []

let dict = ["idCompany": id, "company": companyName, "compType": 
companyType] as [String : Any]
            compArray.add(dict)

id、company 和 compType 来自 SQlite 查询。

我使用 compArray 作为 tableView 数据源。这很好用。不涉及阵列 Controller 。

使用 CDM 加载表如下，CDM 是提供 compArray 的类的实例

//Define the function that will get the data for each cell for each 
//row.
func tableView(_ tableView: NSTableView, objectValueFor tableColumn: NSTableColumn?, row: Int) -> Any? {

    //Define constant dict as an NSDictionary and set to the DM 
    //instance of the DataModel class at the row being loaded into the 
    //table. DM needs to be cast as an NSDictionary. row is passed in as a 
    //parameter by the OS
    let tdict:NSDictionary = CDM.compArray[row] as! NSDictionary

    //Define strKey as the column identifier for the column being 
    //loaded. Column being loaded is passed in as a parameter by the OS
    let strKey = (tableColumn?.identifier)!

    //method will return the value from dict (which is loaded from 
    //CDM.compArray) for the key that is equal to the column identifier 
    //which was loaded to strKey
    return tdict.value(forKey: strKey.rawValue)
}

我想做的是引入一个 NSSearch 字段来搜索 tableview 的所有列。

我添加了搜索字段作为一个 Action ，我还添加了代码以将 compArray 存储到一个名为 backupCompArray 的副本中。

我定义了一个 isSearching 变量:

//The variable is set to true when searching
var isSearching = false {
    //This will be fired if the state of isSearching changes ie false 
    //to true or true to false
    didSet {

        //Test to see whether isSearching now has a new value and if 
        //so we do the housekeeping
        if isSearching != oldValue {

            //If isSearching is now true then it must have previously 
            //been false and we now need to back up the original array
            if isSearching {
                //Back up the original array
                backUpCompArray = compArray
            } else{
                //It is now turning from true to false so need to 
//restore
                compArray = backUpCompArray
            }
        }
    }
}

我希望能够根据搜索字段的 .stringValue 过滤 compArray。

我已将以下内容放入搜索字段的@IBAction 中:

@IBAction func searchField(_ sender: NSSearchFieldCell) {
    if sender.stringValue.isEmpty {
        //If stringValue is empty then cant be searching and this can 
        //trigger the restore of the original array
        isSearching = false
    } else {

        //If stringValue is not empty then must be searching. When the 
        //search starts need to backup the original array
        isSearching = true

        //?????????????
        }
    }

    tableView.reloadData()
}

我需要更换 ?使用可以通过将过滤器应用于 backupCompArray 来设置 compArray 的代码，将任何行返回到 compArray，其中键“company”和“compType”的字典值包含 searchfield.Stringvalue。然后，我可以使用修改后的 compArray 加载仅包含过滤行的表。

所以我尝试了您的代码并遇到了两个错误，我尝试按如下方式修复:

//Can use the .filter method it will iterate each value in the array
        CDM.compArray = backupCompArray.filter(using: {
            // this is where you determine whether to include the 
specific element, $0
            $0["company"]!.contains(sender.stringValue) &&
            $0["compType"]!.contains(sender.stringValue)
            // or whatever search method you're using instead
        })
    }

那是插入 'using' 并将 searchString 更改为 sender.Stringvalue。

但我现在得到:

针对以&&结尾的行

Answer 1

您可以使用 Swift 4 的 Array.filter() 来做到这一点。它需要一个函数，您可以在其中进行计算。您实际上不需要备份您的 compArray，除非您以后需要保留它以备不时之需。

compArray = compArray.filter({
    // this is where you determine whether to include the specific element, $0
    $0["company"]!.contains(searchString) &&
    $0["compType"]!.contains(searchString)
    // or whatever search method you're using instead
})