Filter a nested array and dictionary - ios

Question

I am trying to filter the array which consist of array and dictionary inside it. I want to filter based on the type of the service and then whose isPrimaryMailbox is Yes under attributes array.
This is what I have done:-
let services = Manager.realm().objects(Service.self).filter("type = %#", "MAILBOX")
let serviceWithPrimaryEmail = services.filter({$0.attributes.first?.value == "Yes"})
But this is showing the data which has isPrimaryMailbox value is No
Below is the json response :-
{
"data": {
"cust": [
{
"customerId": "2040349110",
"serv": [
{
"bill": "2010007656959",
"services": [
{
"type": "MOBILE",
"status": "ACTIVE",
"plan": {
"name": "Mobil"
},
"addOns": [
{
"status": "Active"
}
],
"hardware": [
{
"type": "HANDSET"
}
]
},
{
"type": "MOBILE",
"plan": {
"name": "Mobile Service"
},
"addOns": [
{
"status": "Active"
}
],
"hardware": [
{
"type": "HANDSET",
}
]
},
{
"type": "MAILBOX",
"plan": {
"name": "Service"
},
"attributes": [
{
"name": "mailboxSize",
"value": "1 GB"
},
{
"name": "isPrimaryMailbox",
"value": "Yes"
}
]
},
{
"type": "MAILBOX",
"status": "ACTIVE",
"plan": {
"name": "Service"
},
"attributes": [
{
"name": "mailboxSize",
"value": "1 GB"
},
{
"name": "isPrimaryMailbox",
"value": "No"
}
]
}
]
}
]
}
]
}
}

Answer 1

You can try this:
let serviceWithPrimaryEmail = services.filter({$0.attributes.[1].value == "Yes"})
// I used the index 1 because as I see in you JSON data, the isPrimaryMailBox is always in the second row.
Also, your JSON is badly formatted. If you are gonna use an associated Array, then why do you have to separate the key and value to a different key-value pair?
The attributes can simply be:
"attributes": {
"mailboxSize":"1 GB",
"isPrimaryMailbox":true
}
Using boolean instead of string "YES" or "NO"
So that when you filter, you simple say
let serviceWithPrimaryEmail = services.filter({$0.attributes["isPrimaryMailbox"]})
Or if you really prefer the string "YES" then:
let serviceWithPrimaryEmail = services.filter({$0.attributes["isPrimaryMailbox"] == "YES"})

Answer 2

I don't know the type of services object. But here is how you can get primary email service from your JSON:
typealias JSON = [String: Any]
let json = yourJSONDict as? JSON
let services = (((json["data"] as? JSON)?["cust"] as? JSON)?["serv"] as? JSON)?["services"] as? [JSON]
let primaryEmailService = services?.filter { service in
if (service["type"] as? String) == "MAILBOX" {
for attribute in service["attributes"] as? [[String: String]] ?? [] {
if (attribute["name"] == "isPrimaryMailbox") && (attribute["value"] == "Yes") {
return true
}
}
}
return false
}
.first
Edited:
If you don't want to use for loop, you can use filter and reduce only:
let primaryEmailService = services?
.filter {
let attributes = $0["attributes"] as? [[String: String]] ?? []
return ($0["type"] as? String) == "MAILBOX"
&& attributes.reduce(false, { $0 || (($1["name"] == "isPrimaryMailbox") && ($1["value"] == "Yes")) })
}
.first
Please note, that worse case complexity for both approaches are equal. But best case complexity for the first approach is better, because you don't have to loop over all attributes in reduce function. And Swift compiler isn't smart enough for now to stop reduce looping after the first match (false || true always gives true. There is no need to proceed if we have one true).