sort and list JSON array by property in swift

Question

I have the following json array

[
  {
    "name" : "v1",
    "available" : 1
  },
  {
    "name" : "v2",
    "available" : 3
  },
  {
    "name" : "v3",
    "available" : 2
  },
  {
    "name" : "v4",
    "available" : 3
  },
  {
    "name" : "v5",
    "available" : 3
  },
  {
    "name" : "v6",
    "available" : 1
  },
  {
    "name" : "v7",
    "available" : 2
  }
]

the available show some numbers which means: 1 and 3 is ok 2 is not ok

How can I order that json array by available value, showing first the 1 and 3 values and the last the value with 2. The result list should looks like this:

[
  {
    "name" : "v1",
    "available" : 1
  },
  {
    "name" : "v6",
    "available" : 1
  },
  {
    "name" : "v2",
    "available" : 3
  },
  {
    "name" : "v4",
    "available" : 3
  },
  {
    "name" : "v5",
    "available" : 3
  },
  {
    "name" : "v3",
    "available" : 2
  },
  {
    "name" : "v7",
    "available" : 2
  }
]

How can I do that?

Note: I use swiftyJson

This is my code:

sortArrayOddsBeforeEvens(array: json_array)

func sortArrayOddsBeforeEvens(array: JSON){
  let odds = array.filter{ $0.1["available"].intValue % 2 != 0 }
  let evens = array.filter{ $0.1["available"].intValue % 2 == 0 }
  print(odds)
  print(evens)
}

How can I return that as JSON?

create custom element and sort this after append

Ali Ihsan URAL
– Ali Ihsan URAL

2018-10-29 20:07:45 +00:00
Commented Oct 29, 2018 at 20:07 — Ali Ihsan URAL
– Ali Ihsan URAL, Commented Oct 29, 2018 at 20:07
can you write a piece of code?

Israel
– Israel

2018-10-29 20:11:11 +00:00
Commented Oct 29, 2018 at 20:11 — Israel
– Israel, Commented Oct 29, 2018 at 20:11

vadian · Accepted Answer · 2018-10-29 20:43:09Z

1

You are going to sort the array by two criteria.

Suggestion aka usual algorithm: First sort by odd/even, if both values are equal sort by the integer value.

let array = [["name" : "v1", "available" : 1],["name" : "v6", "available" : 1],["name" : "v2", "available" : 3],["name" : "v4", "available" : 3],["name" : "v5", "available" : 3],["name" : "v3", "available" : 2],["name" : "v7", "available" : 2]]

let sortedArray = array.sorted { (d1, d2) -> Bool in
    let avail1 = d1["available"] as! Int
    let avail2 = d2["available"] as! Int
    let compareOddity = avail1 % 2 == 0 && avail2 % 2 != 0
    if compareOddity { return !compareOddity }
    return avail1 < avail2
}

print(sortedArray)

Two avoid ugly boilerplate code drop SwiftyJSON and use Decodable to decode the JSON into structs.
The code will look much cleaner (and is more efficient)

let sortedArray = array.sorted { (d1, d2) -> Bool in
    let compareOddity = d1.available % 2 == 0 && d2.available % 2 != 0
    if compareOddity { return !compareOddity }
    return d1.available < d2.available
}

edited Oct 29, 2018 at 20:43

answered Oct 29, 2018 at 20:37

vadian

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1 Comment

Duncan C Over a year ago

Clever approach. (Voted)

Ryan · Accepted Answer · 2018-10-29 20:46:47Z

0

var array: [Int] = [1, 3, 2, 2, 1, 3, 3, 1, 2, 1, 3, 2, 2, 1]
array.filter({ return $0 != 2 }) + array.filter({ return $0 == 2})

Basically the logic is same.

let data = """
[
{ "name" : "v1", "available" : 1 },
{ "name" : "v2", "available" : 3 },
{ "name" : "v3", "available" : 2 },
{ "name" : "v4", "available" : 3 },
{ "name" : "v5", "available" : 3 },
{ "name" : "v6", "available" : 1 },
{ "name" : "v7", "available" : 2 }]
""".data(using: .utf8)!

let array = JSON(data).arrayValue
let result = array.filter({ return $0["available"].intValue != 2}) + array.filter({ return $0["available"].intValue == 2})

edited Oct 29, 2018 at 20:46

answered Oct 29, 2018 at 20:29

Ryan

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6 Comments

Israel Over a year ago

I need with json array my friend

Ryan Over a year ago

Not much difference in the logic.

vadian Over a year ago

Your code works great if the values are in range 1...3 but it will fail if there are other values.

Ryan Over a year ago

@vadian Seems like there are only 3 cases?

NRitH Over a year ago

All @Ryan has to do to make this work for all values is change those filter conditions into return $0 % 2 == 0 for evens, and return $0 % 2 == 1 for odds.

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