2

I have a tableView with its style being Right Detail. I therefore have 2 arrays, one is for the textLabels data, and the other is for detailTextLabel.

There will be 2 "sort by" options. One will be sort by the textLabels data, and the second will sort by the detailTextlabels data. So when I sort the first array (textLabels array), the second array (detailTextLables array) will also have to get sorted based on the firstarray`.

I know how to sort arrays, but how can I sort one array based on another?

Here's how I sorted the array: (it's an array of Dates.

firstArray.sort({ (a, b) -> Bool in
    a.earlierDate(b) == a
})
Improve this question
7
  • What have you tried and what are you having trouble with? Please include relevant code snippets. See How to Ask Commented Aug 30, 2015 at 22:03
  • 1
    And, FWIW, I would recommend not having 2 separate arrays, but having 1 array with objects in it that have multiple fields. Commented Aug 30, 2015 at 22:03
  • Do you mean a dictionary? Commented Aug 30, 2015 at 22:08
  • No, probably something like struct Item { let text, detailText: String } Commented Aug 30, 2015 at 22:08
  • Or even [(text: String, detailText: String)]. Having two arrays is a mistake. Commented Aug 30, 2015 at 22:17

3 Answers 3

Reset to default
3

First, why not have two arrays? Because you only have one array of UITableViewCells and you want to keep all the data associated with a particular table view cell together. And it makes the need to try to coordinate the sorting of multiple arrays (what you are asking to do) unnecessary.

But if you really want to do that:

var array1 = ["1", "3", "2"]
var array2 = ["One", "Three", "Two"]

let sortedFoo = zip(array1, array2).sort { $0.0 < $1.0 }

array1 = sortedFoo.map { $0.0 }
array2 = sortedFoo.map { $0.1 }

The idea with the above code is that it combines the two arrays into one array of tuples, and then sorts them based on the elements in the first array, then breaks that single array back out into two separate arrays.

In other words, since you have to combine the two arrays into one to do the sort anyway, you might as well make them in a single array in the first place. :-)

Improve this answer
Sign up to request clarification or add additional context in comments.

Comments

2

It's a bit messy, but you can use enumerate to work with indices and elements at the same time:

array1.enumerate().sort {
    return $0.element < $1.element
}.map {$0.element}

array1.enumerate().sort {
    return array2[$0.index] < array2[$1.index]
}.map {$0.element}

But it's really much simpler/easier with one array.

struct Item {
    let prop1: Int
    let prop2: String
}

var array = [
    Item(prop1: 1, prop2: "c"),
    Item(prop1: 2, prop2: "b"),
    Item(prop1: 3, prop2: "a")
]

array.sort { $0.prop1 < $1.prop1 }

array.sort { $0.prop2 < $1.prop2 }
Improve this answer

3 Comments

I'm a newbie in swift, and never worked with structs. How would I add items to this kind of array?
Added an example. I would recommend reading developer.apple.com/library/ios/documentation/Swift/Conceptual/…
Thanks for the answers!! I tried this, and at the line of sort, I get the following error: Cannot invoke 'sort' with an argument list of type '((_, _) -> _)'
2

How about using using positionOf on the sorted array to find the corresponding index in the I sorted array?

Improve this answer

1 Comment

definitely the solution.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.