Method chaining to extract total count of occurrences of a specific value from multiple nested dictionaries

Using Swift
1

I am trying to extract the number of times a specific string value occurs in a group of nested arrays and would like to use something more concise than an if let loop. Using the filter method I am able to export a dictionary from each of the nested dictionaries with just the string value I am looking for, but I can’t collate the vales to count them all:

var returnCounter: [[String] : Int] = [:]

var mondayFruits: [String : [String : Int]] = [Monday : [Orange : 1], Monday : [Apple : 3]]
var tuesdayFruits: [String : [String : Int]] = [Tuesday : [Banana : 2]]
var wednesdayFruits: [String : [String : Int]] = [Wednesday: [Orange : 1], Wednesday: [Banana : 1]]
var thursdayFruits: [String : [String : Int]] = [Thursday: [Apple : 2], Thursday: [Grapes : 12]]
var fridayFruits: [String : [String : Int]] = [Friday : [Banana : 1], Friday : [Apple : 1]]
								



numberOfBananas = value.filter {$0.key.contains(“Banana”)}
//[[“Banana” ]: 2]
//[[“Banana” ]: 1]
//[[“Banana” ]: 1]

Ideally I wanted to chain methods just to extract the number of occurrences and have everything on a single line but got the error: Ambiguous reference to member 'filter'

numberOfBananas = value.filter {$0.key.contains(“Banana”)}.index(forKey: [“Banana”].count)
2

What does your value variable look like? There're only mondayFruits - fridayFruits here. They don't even have String quote. It's interesting how you get it to compile.

3

I am not clear exactly what your question is, but maybe the answer is somewhere in this re‐implementation:

enum Day : CaseIterable {
    case monday
    case tuesday
    case wednesday
    case thursday
    case friday
}
enum Fruit : CaseIterable {
    case apple
    case banana
    case grape
    case orange
}

let records: [Day: [Fruit: Int]] = [
    .monday: [
        .orange: 1,
        .apple: 3
    ],
    .tuesday: [
        .banana: 2
    ],
    .wednesday: [
        .orange: 1,
        .banana: 1
    ],
    .thursday: [
        .apple: 2,
        .grape: 12
    ],
    .friday: [
        .banana: 1,
        .apple: 1
    ]
]

for fruit in Fruit.allCases {
    print(fruit)

    for day in Day.allCases {
        let count = records[day]?[fruit] ?? 0
        // When you want a record for a single day.
        print("\(day): \(count)")
    }

    // When you want the total of all days at once.
    let total = records.values.reduce(into: 0) { $0 += $1[fruit] ?? 0 }
    // Or the same thing more legible but less concise:
    _ = records.values.reduce(into: 0) { (count: inout Int, dayRecord: [Fruit: Int]) in
        count += dayRecord[fruit] ?? 0
    }

    print("Total: \(total)")
    print()
}

(I used enumerations (1) to get easy access to a master list of allCases in order to iterate them during printing, and (2) so I could not accidentally enter a Day as a Fruit or vice‐versa. If those don’t matter and you need them to be String instances for some other reason, the same query logic will still work.)

4

I'd like to formally request this thread be deleted, I will post compilable code again.

5

Apologies for this thread an to those who took the time to help, but I thought it best to start again.

A whiteboard moment.

6

That’s fine.

And I did see your request to have it deleted, but I am not capable of it. (Well, I suppose I could accomplish that by flagging it as a violation of the code of conduct, but that would have other ramifications you don’t want...)

Deleting things isn’t normal on these forums, but I have occasionally seen things marked something like “This post has been withdrawn by its author. It will be removed in x hours unless flagged.” I assume that means a post’s own author has the ability to delete it. I also see a trash can icon under the “...” for posts I’ve authored, so maybe that is what you would have to click if you really want to get rid of this.

7

I did try deleting it but I don't have permission. I think that flagging it will cause me more issues than I care to deal with, so I'll just leave it and be more cautious next time.

Thanks.