Swift: How many of the same object in array

Question

I have a CollectionView with items like...

Fruit(name: String, price: Int, imageUrl: String)

The user can select multiple Fruits and then proceed to a "checkout" which is a UITableView with all the fruits selected. The UITableViewCell contains: amountLabel, fruitLabel, priceLabel.

I want to show how many of each fruit and the total price is, in this view.

What is the best way to do this?

What I see now :

Banana - 1$
Orange - 3$
Banana - 1$
Apple - 2$
Apple - 2$
Banana - 1$
Orange - 3$
Orange - 3$

total: 16$

What I want to see:

3x Banana - 3$
2x Apple - 4$
3x Orange - 9$

total: 16$

You should wrap your Fruit in an Order struct together with an int counter that you increase when the same fruit is added instead of storing a separate fruit. Then you could also have a calculated property in the Order struct that returns the total amount. The Order objects could be stored in a dictionary with the fruit or the fruit name as key — Joakim Danielson
– Joakim Danielson, Commented May 28, 2019 at 8:49
@JoakimDanielson he wants to do that with this data source. That is his question. — Rakesha Shastri
– Rakesha Shastri, Commented May 28, 2019 at 8:49
@RakeshaShastri I posted this as a comment and not as an answer which is quite different so I think I am allowed to present an alternative route for OP to consider. — Joakim Danielson
– Joakim Danielson, Commented May 28, 2019 at 8:54

vadian · Accepted Answer · 2019-05-28 08:51:35Z

2

You could group the array and sum up the prices

let grouped = Dictionary(grouping: fruits, by: {$0.name})
var total = 0
for (key, value) in grouped {
    let price = value.reduce(0, {$0 + $1.price})
    print(value.count, key, "\(price)$")
    total += price
}
print("total: \(total)$")

answered May 28, 2019 at 8:51

vadian

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3 Comments

Fogmeister Over a year ago

Ah yes, I knew there was a Swifty alternative to NSCountedSet but I couldn't remember what it was. This is a better answer than mine :)

maniponken Over a year ago

This was a great answer. Sorry for the late reply but I was trying to populate the cells with the information given. I created a new class FilteredFruits() and a new array [filteredFruits]() and after the print(value.count... I also did filteredFruits.append(Fruit(amount: value.count, name: key, price: price) and then populated the cells with filteredFruits[indexPath.row].name etc. Is this the right way to continue? thanks

vadian Over a year ago

If that's what you expect, yes.

Fogmeister · Accepted Answer · 2019-05-28 08:45:37Z

0

This is a perfect case for NSCountedSet.

You can see the documentation for NSCountedSet here.

You can create an NSCountedSet like...

let countedSet = NSCountedSet(array: fruits)

and then get info out of it like...

countedSet.objectEnumerator.forEach {
    let count = countedSet.count(for: $0)

    print($0.name, count, count * $0.price)
}

For your table view you can use countedSet.objectEnumerator.allObjects.count for the number of rows.

answered May 28, 2019 at 8:45

Fogmeister

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3 Comments

Rakesha Shastri Over a year ago

Can you use this as a data source for a table view?

Rakesha Shastri Over a year ago

Ok. Let me rephrase. Can he use this to get the table view to show the result like how he wants easily? (His last part of the question)

Rakesha Shastri Over a year ago

I am asking if this would work as the data source for the table view to easily achieve his required result format?

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