SOLVED: iExpense Challenge onDelete

@Legion HWS+

Oct '22

I'm stuck on how to delete when there are sections present in the list of expenses.

First I created the two sections using .filter to filter based on Personal vs Business.

            Section {
                ForEach(expenses.items.filter( { $0.type == "Personal" } )) { item in
                    HStack {
                        VStack(alignment: .leading) {
                            Text(item.name)
                                .font(.headline)
                            Text(item.type)
                        }

                        Spacer()
                        amountView(amount: item.amount)
                    }
                }
                .onDelete(perform: removeItems)
            }

            Section {
                ForEach(expenses.items.filter( { $0.type == "Business" } )) { item in
                    HStack {
                        VStack(alignment: .leading) {
                            Text(item.name)
                                .font(.headline)
                            Text(item.type)
                        }

                        Spacer()
                        amountView(amount: item.amount)
                    }
                }
                .onDelete(perform: removeItems)
            }

This doesn't work. It deletes the wrong row. Then I thought I could create two removeItems functions, one called removePersonalItems and one called removeBusinessItems.

I then modified the functions as follows:

func removePersonalItems(at offsets: IndexSet) {
    expenses.items.filter( { $0.type == "Personal" } ).remove(atOffsets: offsets)
}

But this fails as .filter returns an immutable array.

Then I thought maybe I could delete by ID, since ExpenseItem conforms to Identifiable but I can find no way to do so. onDelete doesn't seem to capture the id of the item.

Then I thought maybe there's something I can do with an IndexSet, some method or property that would be of use. But without being able to see what is being sent to removeItems, it's difficult to figure out.

So I figured I'd print the offsets parameter to the console, but using print(offsets) in removeItems does nothing. Nothing is displayed on the console at all.

So what's the solution?

2

@Legion HWS+

Oct '22

The only thing I can think of that would work, which I'll do if there's no solution forthcoming here, would be to have two arrays, one for personal and one for business. The type property would be removed and would instead dictate which array gets the new expense item.

2

@Fly0strich

Oct '22

I didn't use Array.filter I just used if to create my separate sections.

It seems to delete the correct items every time this way. But I remember thinking that it was strange that I didn't have to do anything special to make sure that the proper items were deleted, since Paul specifically mentions that we have to be careful about how we delete the items.

List {
    Section {
        ForEach(expenses.items) { item in
            if item.type == "business" {
                HStack {
                    Text(item.name)
                        .font(.headline)

                    Spacer()

                    Text(item.amount, format: .currency(code: Locale.current.currencyCode ?? "USD"))
                        .foregroundColor(itemColor(itemAmount: item.amount))
                }
            }
        }
        .onDelete(perform: removeItems)
    } header: {
        Text("Business Expenses")
    }

    Section {
        ForEach(expenses.items) { item in
            if item.type == "personal" {
                HStack {
                    Text(item.name)
                        .font(.headline)

                    Spacer()

                    Text(item.amount, format: .currency(code: Locale.current.currencyCode ?? "USD"))
                        .foregroundColor(itemColor(itemAmount: item.amount))
                }
            }
        }
        .onDelete(perform: removeItems)
    } header: {
        Text("Personal Expenses")
    }
}

It's still just using

func removeItems(at offsets: IndexSet) {
    expenses.items.remove(atOffsets: offsets)
}

2

@Bnerd

Oct '22

When you use .filter it returns a NEW array, thus the onDelete using the below

func removeItems(at offsets: IndexSet) {
    expenses.items.remove(atOffsets: offsets)
}

will not work. Making separate arrays will work, but is it worth it? Unless there is a way to modify the removeItems method..tried a bit with no much success

2

	@Legion HWS+ Oct '22 I'm stuck on how to delete when there are sections present in the list of expenses. First I created the two sections using .filter to filter based on Personal vs Business. `Section { ForEach(expenses.items.filter( { $0.type == "Personal" } )) { item in HStack { VStack(alignment: .leading) { Text(item.name) .font(.headline) Text(item.type) } Spacer() amountView(amount: item.amount) } } .onDelete(perform: removeItems) } Section { ForEach(expenses.items.filter( { $0.type == "Business" } )) { item in HStack { VStack(alignment: .leading) { Text(item.name) .font(.headline) Text(item.type) } Spacer() amountView(amount: item.amount) } } .onDelete(perform: removeItems) }` This doesn't work. It deletes the wrong row. Then I thought I could create two removeItems functions, one called removePersonalItems and one called removeBusinessItems. I then modified the functions as follows: `func removePersonalItems(at offsets: IndexSet) { expenses.items.filter( { $0.type == "Personal" } ).remove(atOffsets: offsets) }` But this fails as .filter returns an immutable array. Then I thought maybe I could delete by ID, since ExpenseItem conforms to Identifiable but I can find no way to do so. onDelete doesn't seem to capture the id of the item. Then I thought maybe there's something I can do with an IndexSet, some method or property that would be of use. But without being able to see what is being sent to removeItems, it's difficult to figure out. So I figured I'd print the offsets parameter to the console, but using print(offsets) in removeItems does nothing. Nothing is displayed on the console at all. So what's the solution? 2
	@Legion HWS+ Oct '22 The only thing I can think of that would work, which I'll do if there's no solution forthcoming here, would be to have two arrays, one for personal and one for business. The type property would be removed and would instead dictate which array gets the new expense item. 2
	@Fly0strich Oct '22 I didn't use `Array.filter` I just used `if` to create my separate sections. It seems to delete the correct items every time this way. But I remember thinking that it was strange that I didn't have to do anything special to make sure that the proper items were deleted, since Paul specifically mentions that we have to be careful about how we delete the items. List { Section { ForEach(expenses.items) { item in if item.type == "business" { HStack { Text(item.name) .font(.headline) Spacer() Text(item.amount, format: .currency(code: Locale.current.currencyCode ?? "USD")) .foregroundColor(itemColor(itemAmount: item.amount)) } } } .onDelete(perform: removeItems) } header: { Text("Business Expenses") } Section { ForEach(expenses.items) { item in if item.type == "personal" { HStack { Text(item.name) .font(.headline) Spacer() Text(item.amount, format: .currency(code: Locale.current.currencyCode ?? "USD")) .foregroundColor(itemColor(itemAmount: item.amount)) } } } .onDelete(perform: removeItems) } header: { Text("Personal Expenses") } } It's still just using `func removeItems(at offsets: IndexSet) { expenses.items.remove(atOffsets: offsets) }` 2
	@Bnerd Oct '22 When you use .filter it returns a NEW array, thus the onDelete using the below `func removeItems(at offsets: IndexSet) { expenses.items.remove(atOffsets: offsets) }` will not work. Making separate arrays will work, but is it worth it? Unless there is a way to modify the removeItems method..tried a bit with no much success 2

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