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iOS

Posted by Roland O'Donnell
Roland O'Donnell
5,667 Points

question about this for in loop and how it works

in this piece of code i need some help..

func surroundingPoints(withRange range: Int = 1) -> [Point] {

    var results: [Point] = []
    for xCoord in (x-range)...(x+range) {
        for yCoord in (y-range)...y+range {
            let coordinatePoint = Point(x: xCoord, y: yCoord)
            results.append(coordinatePoint)

// i want to know in what order the for loops are appended to the array so i know exactly whats going on..

What Pasan is saying is the first xCoord x-1 iterates thru the next for in loop so example... [x-1,y-1, x-1,y-0, x-1,y+1, x-0,y-1, x-0,y-0, x-0,y+1 and so on...] i just want to know why if this is the case it dosent just go [x-1,y-1, x-0,y-0, x+1, y+1 and so on..]

hope you understand what I'm asking, thanks

1 Answer

Jennifer Nordell
seal-mask
STAFF
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher
Jennifer Nordell
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher

I think I understand what you're asking. And nested for loops can take a bit to understand! So no worries :smiley: What he's saying here is for every x coordinate do every y coordinate. So we're staring with the x-1 and then listing every possible y coordinate. So we won't move on to the next x coordinate until all the y coordinates are listed out. Then when those are done we move onto the next x coordinate and then list every possible y coordinate with that one. Hope this makes sense! :sparkles: