CODEWITHSUNDEEP
iosswift2
Ash
Ash

Reputation: 149

Finding max element in 2D array in swift

As we have support for Array to find max element using maxElement(), do we have any method using which we find max element in a 2D array Array<Array<Double>> in swift-2.0? Or do we need to write our own method?

Upvotes: 1

Views: 2296

Answers (4)

P. Stern
P. Stern

Reputation: 351

You can use flatMap to convert to a 1D array, then take the max of that...

let max = matrix.flatMap { $0 }.max()

max is Optional(9)

Upvotes: 0

Gargo
Gargo

Reputation: 1380

The most optimized and universal solution:

struct CustomObject {
  var date: Date
}

let objectComparator = { (p1: CustomObject, p2: CustomObject) in
            p1.date > p2.date
        }
        let result = params.compactMap {
            $0.max(by: objectComparator)
        }
            .max(by: objectComparator)

After compactMap you get a flatten array which consists of max elements from the nested arrays. Then you apply max for the second time.

This code uses as little memory and cpu as possible.

Upvotes: 0

S At
S At

Reputation: 467

    import UIKit

var val= [
    [2, 4, 9],
    [3, 6, 0],
    [8, 7]
]

func raiseLowerValue(inout val: [[Int]]) {
    for row in 0..<image.count {
        for col in 0..<image[row].count {
           if image[row][col] < 5 {
              image[row][col] = 5
           }
        }
    }
}

by substituting "if" you can use by sort! or the other way.

Upvotes: 0

Moriya
Moriya

Reputation: 7906

I don't know of any built in support for that but I suppose this is a simple enough solution

var matrix = [[3,5,4,6,7,],[9,2,6,8,3,5],[1,2,6,7,8,4]]

let max = matrix.maxElement({ (a, b) -> Bool in
    return a.maxElement() < b.maxElement()
})?.maxElement()

max is Optional(9) in this case

or you can use map for the same

let max2 = matrix.map({ (a) -> Int in
    return a.maxElement()!
}).maxElement()!

shorter version

let max3 = matrix.map({ $0.maxElement()!}).maxElement()!

Upvotes: 0

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