Club Values of array - ios

Question

I am writing an iOS App in Swift 4.2.
I am geting JSON array which I convert into Swift object of Class Sector
JSON:
"Sector": [
{
"REPSECTOR": "TELECOM - SERVICES",
"PERC_HOLD": 5.6,
"CO_NAME": "REVERSE REPO"
},
{
"REPSECTOR": "TELECOM - SERVICES",
"PERC_HOLD": 1.0,
"CO_NAME": "BHARTI AIRTEL"
},
{
"REPSECTOR": "FERROUS METALS",
"PERC_HOLD": 0.3,
"CO_NAME": "COAL INDIA"
}
]
Class:
class Sector{
var REPSECTOR:String=""
var PERC_HOLD:Double=0.0
var CO_NAME:String=""
}
I am making Array array1 of type [Sector] from above.
I need to make a new array from above array which must be clubed/combined values based on REPSECTOR variable, and total of PERC_HOLD.
Expected Result:
new array with 2 elements:
1: TELECOM - SERVICES, 5.6+1.0
2: FERROUS METALS, 0.3

Answer 1

Suppose the array you've decoded is called array :
var array: [Sector]()
Let's create a dictionary of sectors that have the same REPSECTOR property :
let dict = Dictionary(grouping: array) {
$0.REPSECTOR
}
Now let's create an new array with sectors that have the same name, and sum their PERC_HOLD :
var newArray = [Sector]()
for (key, value) in dict {
let sector = Sector()
sector.REPSECTOR = key
sector.PERC_HOLD = value.reduce(0, { $0 + $1.PERC_HOLD })
newArray.append(sector)
}
You could check the result this way :
for s in newArray {
print(s.CO_NAME, s.PERC_HOLD)
}

Answer 2

First, I think you should use proper casing in your Sector type, and use Codable. For your type it would be trivial:
struct Sector: Codable {
let repsector: String
let percHold: Double
let coName: String
enum CodingKeys: String, CodingKey {
case repsector = "REPSECTOR"
case percHold = "PERC_HOLD"
case coName = "CO_NAME"
}
}
Then, assuming we have JSON like this:
let sectorsJSON = """
[
{
"REPSECTOR": "TELECOM - SERVICES",
"PERC_HOLD": 5.6,
"CO_NAME": "REVERSE REPO"
},
{
"REPSECTOR": "TELECOM - SERVICES",
"PERC_HOLD": 1.0,
"CO_NAME": "BHARTI AIRTEL"
},
{
"REPSECTOR": "FERROUS METALS",
"PERC_HOLD": 0.3,
"CO_NAME": "COAL INDIA"
}
]
""".data(using: .utf8)!
Then we can decode your JSON like this:
let decoder = JSONDecoder()
let rawSectors = try decoder.decode([Sector].self, from: sectorsJSON)
And then we can group it by .repsector and sum up percentages:
let groupedSectors = Dictionary(grouping: rawSectors, by: { $0.repsector })
.map { (arg) -> (String, Double) in
let (key, value) = arg
let percents = value.reduce(into: 0, { (acc, sector) in
acc += sector.percHold
})
return (key, percents)
}
print(groupedSectors) // [("FERROUS METALS", 0.3), ("TELECOM - SERVICES", 6.6)]

Answer 3

let dicSector = ["Sector": [
[
"REPSECTOR": "TELECOM - SERVICES",
"PERC_HOLD": 5.6,
"CO_NAME": "REVERSE REPO"
],
[
"REPSECTOR": "TELECOM - SERVICES",
"PERC_HOLD": 1.0,
"CO_NAME": "BHARTI AIRTEL"
],
[
"REPSECTOR": "FERROUS METALS",
"PERC_HOLD": 0.3,
"CO_NAME": "COAL INDIA"
]
]]
Codable Sector
class Sector: Codable {
var REPSECTOR:String=""
var PERC_HOLD:Double=0.0
var CO_NAME:String=""
}
Convert Dictonary to object array
var arraySector = [Sector]()
if let array = dicSector["Sector"] {
do {
let data = try JSONSerialization.data(withJSONObject: array, options: JSONSerialization.WritingOptions.prettyPrinted)
let jsonDecoder = JSONDecoder()
arraySector = try jsonDecoder.decode([Sector].self, from: data)
}
catch {
print(error.localizedDescription)
}
}
Array To Grouping
let predicate = { (element: Sector) in
return element.REPSECTOR
}
let dic = Dictionary(grouping: arraySector, by: predicate)
print(dic)
Output
["TELECOM - SERVICES": [Sector, Sector], "FERROUS
METALS": [Sector]]

Answer 4

This is not the best solution but working
var newArray = [Sector]()
oldArray.forEach() { element in
if newArray.contains(where: { $0.REPSECTOR == element.REPSECTOR }) {
newArray.forEach() { newElement in
if newElement.REPSECTOR == element.REPSECTOR {
newElement.CO_NAME + element.CO_NAME
} else {
newArray.append(element)
}
}
} else {
newArray.append(element)
}
}