CODEWITHSUNDEEP
iosswift
Guillermo Alvarez
Guillermo Alvarez

Reputation: 1775

Error in closure cannot invoke 'filter' with an argument list of type '((_) -> _)' when filtering [NSDictionary]

I have a son file which is an array of dictionary entries. A sample entry looks like

{"title":"Limits - Evaluating Limits by Graphing mini lecture","chapter":"2","section":"1","path":"chap2/","fileName":"2.1-1-Limits-Evaluating_Limits_by_Graphing_mini_lecture.mp4"}

I want to filter the entries out by chapter and save them into an array. So I have the following lines of code:

currentChapter = "2"//just an example 

let parsedObject:AnyObject? = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.AllowFragments, error: &parseError)

if let videoList = parsedObject as? [NSDictionary] {
            let videoListForChapter = videoList.filter {$0["chapter"] == self.currentChapter}
}

Upvotes: 0

Views: 69

Answers (1)

Kris Gellci
Kris Gellci

Reputation: 9687

You are using .filter on NSDictionary, it should work as you would expect if you were using just Dictionary.

Try changing the code to the following

let parsedObject = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.AllowFragments, error: &parseError) as [Dictionary<String: String>]

Then remove the if statement and you are left with

let videoListForChapter = parsedObject.filter {$0["chapter"] == self.currentChapter}

Here is some code you can copy and paste into a playground based on your sample entry:

var array : [[String:String]] = [["title":"Limits - Evaluating Limits by Graphing mini lecture",
    "chapter":"2",
    "section":"1",
    "path":"chap2/",
    "fileName":"2.1-1-Limits-Evaluating_Limits_by_Graphing_mini_lecture.mp4"],
    ["title":"test Title",
        "chapter":"1",
        "section":"1",
        "path":"chap2/",
        "fileName":"2.1-1-Limits-Evaluating_Limits_by_Graphing_mini_lecture.mp4"]]

array[0]
let videoListForChapter = array.filter {$0["chapter"] == "2"}

videoListForChapter

Upvotes: 1

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