Array after an element is > 0 change all elements to that value until next non zero value - arrays

Question

I have an array that is for example
[0.0, 0.0, 55.0, 0.0, 0.0, 55.0, 55.0, 22.0, 0.0, 55.0]
How can I change the element with 0 value if the previous value > 0? so
[0.0, 0.0, 55.0, 0.0, 0.0, 55.0, 55.0, 22.0, 0.0, 55.0]
becomes
[0.0, 0.0, 55.0, 55.0, 55.0, 55.0, 55.0, 22.0, 22.0, 55.0]
I have tried the following and it removes the zeros and nothing else.
func weightArrayRemovedZero(array: [Double])->[Double]{
var arrayToAlter = [Double]()
for(index,item) in array.enumerated() {
print("The \(item) is at index:\(index)")
if item == 0.0 {
if index > 0 && index < array.count - 1 {
if array[index - 1] != 0.0 {
let nonZeroElement = array[index - 1]
arrayToAlter.append(nonZeroElement)
}
}
} else {
arrayToAlter.append(item)
}
}
return arrayToAlter
}

Answer 1

map seems to be the natural approach to me:
var last = 0.0
let mapped = values.map { elem -> (Double) in
last = elem > 0.0 ? elem : last
return last
}
Generally speaking, map is your go to when you want to change one collection into another collection with a one-to-one element mapping.

Answer 2

Try this out
var array = [0.0, 0.0, 55.0, 0.0, 0.0, 55.0, 55.0, 22.0, 0.0, 55.0]
array.enumerated().forEach {
array[$0] = $1 == 0 &&
array.indices.contains($0 - 1) &&
array[$0 - 1] > 0 ? array[$0 - 1] : $1
}
print(array)

Answer 3

Another option:
var array = [0.0, 0.0, 55.0, 0.0, 0.0, 55.0, 55.0, 22.0, 0.0, 55.0]
for i in array.indices {
if i == 0 { continue }
if array[i] == 0 && array[i-1] != 0 {
array[i] = array[i-1]
}
}
// [0, 0, 55, 55, 55, 55, 55, 22, 22, 55]