CODEWITHSUNDEEP
iosarraysdictionaryswift4
Harry P
Harry P

Reputation: 21

Compare the key with array of dictionaries in iOS swift 4

I am trying to compare the studentId with the array of dictionaries which has multiple studentId's. I need to get the dictionary which matches with the particular StudentID..Can any one please suggest the perfect solution. I am new to swift.

"students" : [
    {
      "studentId" : "STUDENT123456789",
      "middleName" : "Evangeline",
      "firstName" : "Dia",
      "rollNo" : "1001",
      "studentClass" : {
        "className" : "Grade 10",
        "classId" : "CLASS123456789",
      }
    }
  {
      "studentId" : "STUDENT14354678960",
      "middleName" : "Joseph",
      "firstName" : "Parker",
      "rollNo" : "1002",
      "studentClass" : {
        "className" : "Grade 10",
        "classId" : "CLASS15468975467",
      }
    }
  ]

I have students array which is an array of dictionaries.Now I have to compare student Id with this existing array containing multiple studentID's. so when it matches with the student ID, I need to get that particular dictionary data. For example, I have studentId as "STUDENT14354678960" so I need to get the data containing related to this Id..

Upvotes: 0

Views: 1719

Answers (2)

ahbou
ahbou

Reputation: 4918

You can use where with a closure:

let search = students.first { (element) -> Bool in
    if let dict = element as? [String:Any] {
        return dict["studentId"] == yourID
    }
}

Upvotes: 2

vadian
vadian

Reputation: 285079

Use first, it returns the first found object or nil

if let student = students.first(where: {$0["studentId"] as! String == "STUDENT123456789"}) {
   print(student["firstName"])
} else {
   print("not found")
}

It's highly recommended to use a custom struct or class for the student data for example

let jsonString = """
{"students" : [
{"studentId" : "STUDENT123456789", "middleName" : "Evangeline", "firstName" : "Dia", "rollNo" : "1001", "studentClass" : { "className" : "Grade 10", "classId" : "CLASS123456789"}},
{"studentId" : "STUDENT14354678960", "middleName" : "Joseph", "firstName" : "Parker", "rollNo" : "1002", "studentClass" : {"className" : "Grade 10", "classId" : "CLASS15468975467"}}
]}
"""

struct Root : Decodable {
    let students : [Student]
}

struct Student : Decodable {
    let studentId, middleName, firstName, rollNo : String
    let studentClass : StudentClass
}

struct  StudentClass : Decodable {
    let className, classId : String
}

let data = Data(jsonString.utf8)
do {
    let result = try JSONDecoder().decode(Root.self, from: data)
    let students = result.students
    if let student = students.first(where: {$0.studentId == "STUDENT123456789" }) {
        print(student)
    }
} catch {
    print(error)
}

Upvotes: 3

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