how to create json object in ios swift

to answer your question.

 var person = ["ABC","XYZ","PQR"]
    var email = ["[email protected]","[email protected]","[email protected]"]
    var mobile = ["1234567890","1234567890","1234567890"]


    var paramCollection = [Any]()

    var index = 0
    for personData in person {
        var dataCollection = [String:Any]()
        dataCollection["person"] = personData
        dataCollection["email"] = email[index]
        dataCollection["contact"] = mobile[index]
        paramCollection.append(dataCollection)
        index += 1
    }

    let finalParameter = ["blogs":paramCollection]
}

//This will do the trick but to make it more robust you should rethink your design
// maybe use struct to store a persons data
struct Blog {
    var person: String
    var email: String
    var mobile: String

    init(name:String, email:String, phone:String) {
        self.person = name
        self.email = email
        self.mobile = phone
    }
}

//and instead of having three arrays holding three different property, you can have one array of
var blogArray = [Blog]()

//You understand where I'm going with this

This is not a great design by choice to have multiple arrays relating to the data of same Entity.

Ideally create an Entity Model called Blog with fields like personName, email, mobileNo like below -

struct Blog {

var personName: String?
var email: String?
var mobileNo: String?
}

And then in your code have an array of this to save the data then you can directly convert it into Json using the link

Convert Custom Structs to Json

Try this:

let jsonObject: [String: Any]?
let array: [[String: Any]] = [[:]]

    for i in 0..person.count {
    let dict = ["person": person[i],
        "email": email[i],
        "contact": mobile[i]]
    array.append(dict)
    }
    jsonObject = ["blogs": array]

let validateJson = JSONSerialization.isValidJSONObject(jsonObject)
if validateJson {
  //Go Ahead
}

let dictionary = ["key1": "value1", "key2": "value2"] 
let jsonData = try? JSONSerialization.data(withJSONObject: dictionary, options: .prettyPrinted) 
// Verifying it worked: 
let parsedObject = try! JSONSerialization.jsonObject(with: jsonData!, options: .allowFragments)