Htykuut

How to group Arrays by a first same elements
for example I have Array like that"

var Array = ["1","1","1","2","2","1","1"]

I want to group the Array like :

groupedArray = [

        ["1","1","1"],

        ["2","2"],

        ["1","1"]

    ]

Thank you!

You can extend Collection, constrain its Element to Equatable protocol and create a computed property to return the grouped elements using reduce(into:) method. You just need to check if there is a last element on the last collection equal to the current element and append the current element to the last collection if true otherwise append a new collection with it:

extension Collection where Element: Equatable {

    var grouped: [[Element]] {

        return reduce(into: ) {

            $0.last?.last == $1 ?

            $0[$0.index(before: $0.endIndex)].append($1) :

            $0.append([$1])

        }

    }

}

let array = ["1","1","1","2","2","1","1"]

let grouped = array.grouped

print(grouped)  // "[["1", "1", "1"], ["2", "2"], ["1", "1"]]n"

Don't name your variable Array, you are masking the Swift.Array type and will cause untold number of weird bugs. Variable names in Swift should start with a lowercase letter.

Use prefix(while:) to gather identical elements starting from a specified index. And then you keep advancing that index:

let array = ["1","1","1","2","2","1","1"]



var index = 0

var groupedArray = [[String]]()

while index < array.count {

    let slice = array[index...].prefix(while: { $0 == array[index] })

    groupedArray.append(Array(slice))

    index = slice.endIndex

}