Filtering Array and displaying in Table View?

问题:

I want to search an dictionary of exercises for the name key and then show the filtered result in the table view. I am using this function

func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
    let filtered = exercises.filter { $0["name"] == searchText }
    print(filtered)

    if(filtered.count == 0){
        searchActive = false;
    } else {
        searchActive = true;
    }
    self.exercisesTableView.reloadData()
}

Variables:

var exercises = [Exercise]()
var filtered: [NSMutableArray] = []
var searchActive: Bool = false

In the search function I get the error

Type'Exercise' has no subscript members

and then i have the issue that the result is an NSMutableArray and so I cant set the result names as cell text to display

Cannot convert value of type 'NSMutableArray' to type 'String' in coercion

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
    if (searchActive){
        cell.textLabel?.text = filtered[indexPath.row] as String
    } else {
        let exercise = exercises[indexPath.row]

        cell.textLabel!.text = exercise.name
    }
    return cell
}

Here is my Exercise dictionary for reference:

final public class Exercise {
    var id: Int
    var descrip: String
    var name: String
    var muscles: [Int]
    var equipment: [Int]

    public init?(dictionary: [String: Any]) {

        guard
            let id = dictionary["id"] as? Int,
            let descrip = dictionary["description"] as? String,
            let name = dictionary["name"] as? String,
            let muscles = dictionary["muscles"] as? [Int],
            let equipment = dictionary["equipment"] as? [Int]

            else { return nil }

        self.id = id
        self.descrip = descrip
        self.name = name
        self.muscles = muscles
        self.equipment = equipment

    }

I can fix the second error by making var filtered: [String] = [] so it can be used as a cell title, but that doesnt resolve the first error and im not sure is the right way to go about it?

回答1:

Your filtered also type of [Exercise] and you need to filter it like.

var filtered = [Exercise]() 

self.filtered = exercises.filter { $0.name == searchText }

Here $0 is type of Exercise object, so you need to access its property name using $0.name.

Edit: If you want filtered as type of [String] with only name then you can need to use both map and filter like this.

self.filtered = exercises.filter { $0.name == searchText }.map { $0.name }

OR

self.filtered = exercises.map { $0.name }.filter { $0 == searchText }

OR directly using filterMap as @dfri suggested.

self.filtered = exercises.flatMap{ $0.name == searchText ? $0.name : nil }

回答2:

I told you yesterday forget the dictionary semantics when using a custom class.
Do not use key subscripting!

As mentioned in the other answers you have to declare filtered also as [Exercise]

var filtered = [Exercise]() 

and filter

self.filtered = exercises.filter { $0.name == searchText }

However if you want to search also for partial strings use

self.filtered = exercises.filter {$0.name.range(of: searchText, options: [.anchored, .caseInsensitive, .diacriticInsensitive]) != nil }

But

since both filtered and unfiltered arrays are of type [Exercise] you have to change cellForRowAtIndexPath this way

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
    let exercise : Exercise 
    if (searchActive){
        exercise = filtered[indexPath.row]
    } else {
        exercise = exercises[indexPath.row]
    }
    cell.textLabel!.text = exercise.name
    return cell
}

回答3:

The issue here is $0["name"] == searchText. $0 in this context is of Excersise type and you refer to it as it's an array. This line should look like this:

let filtered = exercises.filter { $0.name == searchText }

回答4:

In my case I have used the following code in some personal projects, the code is very similar to the previous answers. I just use contains.

func filter(query: String){
        if query.isEmpty {
            self.filteredData = self.originalData
        } else {
            self.filteredData = self.originalData.filter {
                $0.prop1!.lowercased().contains(query)
            }
        }
    }