Adding to dictionary dynamically - ios

Question

I 'm having an array of dictionary like so...
[
{
"id" : "3",
"sellingPrice" : "520",
"quantity" : "15"
},
{
"id" : "5",
"sellingPrice" : "499",
"quantity" : "-1"
},
{
"id" : "8",
"sellingPrice" : "500",
"quantity" : "79"
}
]
Now I want to add to the dictionary another key called remaining_balance with a value of 420,499 & 500 respectively. How can I achieve this..? Hope somebody can help...

Answer 1

It seems like you want to add a value to your dictionary that is an array:
var arrDict = Array<Dictionary<String,Any>>() //Your array
arrDict.append(["id":"3","sellingPrice":"520","quantity":"13"])
arrDict.append(["id":"5","sellingPrice":"43","quantity":"32"])
arrDict.append(["id":"8","sellingPrice":"43","quantity":"33"])
let arrValue = ["420","499","500"] //Your remaining value in array
print("Before ",arrDict)
for (index,dict) in arrDict.enumerated() {
var dictCopy = dict //assign to var variable
dictCopy["remaining_balance"] = arrValue[index]
arrDict[index] = dictCopy //Replace at index with new dictionary
}
print("After ",arrDict)
EDIT
If you are able keep an index of an array it would be possible,
Assuming that you have the index of an array
var dictCopy = arrDict[index]
dictCopy["remaining_balance"] = "666" //Your calculated value
arrDict[index] = dictCopy //Replace at index with new dictionary

Answer 2

var newKV = [["remaining_balance": "420"],["remaining_balance": "490"],["remaining_balance": "500"]]
let array = [["id":"3", "sellingPrice":"520", "quantity":"15"], ["id":"5", "sellingPrice":"520", "quantity":"15"], ["id":"8", "sellingPrice":"520", "quantity":"15"]]
let newArray = array.enumerated().map { (index : Int, value: [String: String]) -> [String: String] in
var dic = value
dic.merge(newKV[index]) { (_, new) -> String in
new
}
return dic
}

Answer 3

You could achieve it by mapping your array:
var myArray = [["id": "3", "sellingPrice": "520", "quantity" : "15"], ["id": "5", "sellingPrice": "499", "quantity" : "-1"], ["id": "8", "sellingPrice": "500", "quantity" : "79"]]
print(myArray)
/*
[["id": "3", "sellingPrice": "520", "quantity": "15"],
["id": "5", "sellingPrice": "499", "quantity": "-1"],
["id": "8", "sellingPrice": "500", "quantity": "79"]]
*/
print("___________________")
var remainingBalanceDesriedValue = 420
myArray = myArray.map { (dict: [String: String]) -> [String: String] in
var copyDict = dict
copyDict["remaining_balance"] = "\(remainingBalanceDesriedValue)"
remainingBalanceDesriedValue = (remainingBalanceDesriedValue == 420) ? 499 : (remainingBalanceDesriedValue == 499) ? 500 : 420
return copyDict
}
print(myArray)
/*
[["sellingPrice": "520", "quantity": "15", "id": "3", "remaining_balance": "420"],
["sellingPrice": "499", "quantity": "-1", "id": "5", "remaining_balance": "499"],
["sellingPrice": "500", "quantity": "79", "id": "8", "remaining_balance": "500"]]
*/

Answer 4

Let's assume you have an array of dictionaries like so:
var arrayOfDictionaries = [
[
"id": 3,
"sellingPrice": 520,
"quantity": 15
]
]
It is important that arrayOfDictionaries is not a let constant, otherwise it is considered immutable and you can not call append on it.
Now you init a new dictionary like:
let newDictionary = [
"id": 10,
"remaining_balance": 420,
"quantity": 15
]
Now add the newDictionary like
arrayOfDictionaries.append(newDictionary)
If the order is important
If the order is important there are a couple of ways to go about that.
When calling append the new value (in this case the new dictionary) will always be inserted at the bottom of the array.
If for some reason you can not call append in the correct order you could use insert, which inserts your dictionary at a specific position.
Yet another way is to append the values wildly and after you are done, call sort on the array.
Improvement Tips
Notice that for the values I did not use strings, as you only have numbers like "id" : 30.
Also, if you want the second key to be called remaining_balance you should call the first key selling_price instead of sellingPrice. Because of conistency.
Alternative approach
As far as I have understood you are trying to implement some software that is responsibly for selling some products.
I think you are tackling this problem from a completely wrong side.
I think you should read about database relationships. Selling products actually is a very common problem.
Maybe this will help you. I would offer a possible solution myself, but I think this misses the point of your question.
If you decide to use the database approach, you won't necessarily have to use a database. You can take the approach and implement it using simple structs/classes/arrays.

Answer 5

I noticed this question lacks an extension answer, yes.. I'm gonna be that guy, so here it is. This could be made more generic by supporting other types of dictionaries, feel free to pitch in ;)
Inspiration from #eason's answer.
var newKV = [["remaining_balance": "420"],["remaining_balance": "490"],["remaining_balance": "500"]]
var array = [["id":"3", "sellingPrice":"520", "quantity":"15"], ["id":"5", "sellingPrice":"520", "quantity":"15"], ["id":"8", "sellingPrice":"520", "quantity":"15"]]
extension Array where Element == [String: String] {
enum UniquingKeysStrategy {
case old
case new
}
mutating func merge(with target: Array<Element>, uniquingKeysWith: UniquingKeysStrategy = .new) {
self = self.merged(with: target)
}
func merged(with target: Array<Element>, uniquingKeysWith strategy: UniquingKeysStrategy = .new) -> Array<Element> {
let base = self.count > target.count ? self : target
let data = self.count > target.count ? target : self
return data.enumerated().reduce(into: base, {
result, data in
result[data.offset]
.merge(data.element, uniquingKeysWith: {
old, new in
if strategy == .new { return new }
return old
})
})
}
}
let mergedArrays = newKV.merged(with: array, uniquingKeysWith: .old)
array.merge(with: newKV)
Happy Coding :)