CODEWITHSUNDEEP
arraysswift
vpoltave
vpoltave

Reputation: 1770

Short solution to find indexes

Function is filtered indexes of equal years in one array from another.

I'm looking for shorter solution of my code:

 let years = (2015...2025).map { $0 }
 var chosenYears = [2015, 2019, 2016] (example)

This function does what i want, but i'm looking for something (more functional-programming look).

 func selectChoseYears() {
    for (index, year) in years.enumerated() {
        for chosenYear in chosenYears {
            if year == chosenYear { view?.selectCell(at: index) }
        }
    }
 }

I tried some solutions, but they look ugly and longer than this.

Thank you.

Upvotes: 0

Views: 110

Answers (5)

CZ54
CZ54

Reputation: 5588

try :

let result = (2015...2025).map { $0 }.filter { [2015, 2019, 2016].contains($0)}

Upvotes: 0

Mojtaba Hosseini
Mojtaba Hosseini

Reputation: 119302

You can find indexes of any Equatable elements with the following function

- General index finder

func indexes<T: Equatable>(of chosen: [T], in all: [T]) -> [Int] {
    return all.enumerated().filter { chosen.contains($0.element) }.map { $0.offset }
}

- Usage:

indexes(of: chosenYears, in: years)

Upvotes: 1

vadian
vadian

Reputation: 285079

You can filter the indices directly

years.indices.filter{ chosenYears.contains(years[$0]) }.forEach { view?.selectCell(at: $0) }

I totally agree with Sulthan's comment. However I would replace more readable and simpler with more efficient

Upvotes: 2

tomieq
tomieq

Reputation: 29

You might try something like this:

self.tableView.visibleCells
.flatMap { $0 as? MyCell }
.forEach { $0.updateView(isSelected: chosenYears.contains($0.viewModel?.year) }

Although it requires that the cells store view model with the year it represents and you need to implement updateView(isSelected:)

Upvotes: 0

Sulthan
Sulthan

Reputation: 130102

There are many possible solutions, for example:

let yearIndices = chosenYears.compactMap { years.index(of: $0) }
for yearIndex in yearIndices {
   view?.selectCell(at: yearIndex)
}

or just

for (index, year) in years.enumerated() where chosenYears.contains(year) {
    view?.selectCell(at: index)
}

Upvotes: 4

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