Math operations individual elements in 2D Array - Swift - arrays

Question

I’m trying to perform different mathematical operations on individual elements of a 2D array (testArray) combined with 1D array (mod). I’ve got the following for generating individual variables but can’t figure out how to get these values back into a new 2D array. Swift 3.0.2.
let testArray: [[Double]] =
[[0,100,20.1],
[1,99,19.2],
[3,98,18.2],
[5,97,17.3],
[7,96,16.4],
[9,95,15.5]]
let mod: [Double] = [0,5,7,14,20,22]
//Math operations on the two above arrays
for var x in 0..<testArray.count {
var result1 = Double(testArray[x][0])
var result2 = Double(testArray[x][1] + mod[x])
var result3 = Double(testArray[x][2] - mod[x])
print(result1,result2,result3)
}
//output is as follows:
0.0 100.0 20.1
1.0 104.0 14.2
3.0 105.0 11.2
5.0 111.0 3.3
7.0 116.0 -3.6
9.0 117.0 -6.5
//how do I get the same numbers into a new 2D array as follows:
[[0.0,100.0,20.1],
[1.0,104.0,14.2],
[3.0,105.0,11.2],
[5.0,111.0,3.3],
[7.0,116.0,-3.6],
[9.0,117.0,-6.5]]

Answer 1

It could be as simple as this,
var anotherArray: [[Double]] = []
for x in 0..<testArray.count {
let result1 = Double(testArray[x][0])
let result2 = Double(testArray[x][1] + mod[x])
let result3 = Double(testArray[x][2] - mod[x])
anotherArray.append([result1, result2, result3])
}
print(anotherArray)

Answer 2

You can use map:
let result = testArray.indices.map { [ testArray[$0][0], testArray[$0][1] + mod[$0], testArray[$0][2] - mod[$0] ] }
On a side note, your for block can be written as:
for x in testArray.indices {
let result1 = testArray[x][0]
let result2 = testArray[x][1] + mod[x]
let result3 = testArray[x][2] - mod[x]
print(result1,result2,result3)
}