Q:
How to remove duplicate row from UITableView?
I have the following data inside an array which is used as a source in a UITableView:
array = [
{user : "A" },
{user : "B" },
{user : "C" },
{user : "D" }
]
Then I add the data into the tableView:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "reusableCell", for: indexPath) as! TableViewCell
let user = array[indexPath.row]
cell.title.text = user["user"] as? String
return cell
}
But in my table, I want to show the data like this without repeating the username:
user A
user B
user C
user D
Here is my current setup:
A:
Use below Code to get the required result
let sortedArray = (array.map { $0["user"] as? String }) ?? [] // This will not return nil
var sortedKeys = Set()
var keys = array.map { $0["user"] as! String }
for key in keys {
if sortedKeys.contains(key) {
sortedKeys.insert(key)
} else {
sortedKeys.insert(sortedArray.index(of: key) ?? key) // to get the last index of key if key not exist in array
}
}
let unsortedKeys = sortedKeys.sorted()
let result = sortedKeys.map { unsortedKeys[$0]! }
// result is ["A", "B", "C", "D"]
And now your UITableView dataSource method will be like
let filteredArray = (array.map { $0["user"] as? String }) ?? [] // This will not return nil
var filteredKeys = Set()
var keys = array.map { $0["user"] as! String }
for key in keys {
if filteredKeys.contains(key) {
filteredKeys.insert(key)
} else {
filteredKeys.insert(filteredArray.index(of: key) ?? key) // to get the last index of key if key not exist in array
}
}
let unfilteredKeys = filteredKeys.sorted()
let result = filteredKeys.map { unfilteredKeys[$0]! }
// result is ["A", "B", "C", "D"]
And for the TableView
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return result.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "reusableCell", for: indexPath) as! TableViewCell
let user = array[indexPath.row]
cell.title.text = user["user"] as? String
return cell
}
Hope This helps..!
A:
let sorted = array.sorted(by: {$0["user"] as! String < $1["user"] as! String})
let keys = sorted.map {$0["user"] as! String}
let filtered = sorted.map {$0["user"] as! String}
let filteredKeys = keys.sorted()
let result = sortedKeys.map { filtered[$0]! }
Note: This solution will works for you perfectly with Swift 3
A:
You can use this elegant solution:
let items = [
["user": "A"],
["user": "B"],
["user": "C"],
["user": "D"]
]
let orderedItems = items.sorted(by: {$0["user"] < $1["user"]})
let filteredItems = orderedItems.map{ $0["user"] }
print(filteredItems) // A, B, C, D
Edit:
Use this variant to add index numbers in order:
let items = [
["user": "A"],
["user": "B"],
["user": "C"],
["user": "D"]
]
let orderedItems = items.sorted(by: {$0["user"] < $1["user"]})
let filteredItems = orderedItems.map{ [String($0["user"]!): $0["user"]!] }
let filteredKeys = filteredItems.map{ $0.keys.map{String($0)!}.sorted() }
print(filteredItems) // [["user": "B"], ["user": "C"], ["user": "A"], ["user": "D"]]
print(filteredKeys) // ["C", "B", "A", "D"]
Explanation:
In this solution we create a filteredItems, it is an array of dictionaries, like:
[["A",1],["B",2],["C",3],["D",4]]
We also create a filteredKeys array, it contains number labels as the first key and the names as the second key:
[1:"A",2:"B",3:"C",4:"D"]
Then we filter the items by keys, and sort them by keys in an order ([4,"D",3,"C",2,"B",1,"A"]),
and then we get the number labels as the first key and the names as the second.
Result:
$ scala
Welcome to Scala 2.13.0 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_25).
Type in expressions for evaluation. Or try :help.
scala> val items = Seq(Seq(("user", "A"), ("user", "B")), Seq(("user", "C"), ("user", "D")))
items: Seq[Seq[(String, String)]] = List((user,A), (user,B), (user,C), (user,D))
scala> val orderedItems = items.sorted(by: { case ((x:
