Sorting elements in an Array

Community Help
1

Hello Folks,
I’m trying to sort an array row-wise. The array contains coordinate points (x, y). I tried to sort the array but I am not getting the expected result. Any help will be highly appreciated.
Link to my notebook: Sorting elements in an Array / JS | Observable

Expected outcome

SortedArray =  Array(2) [
  0: Array(3) 
[0: Object{x: 56.71095406360424, y: 60.00740978691508}  
  1:  Object {x: 173, y: 52.6015625}
  2: Object {x: 306, y: 49.6015625}
]
  1: Array(3) [
  0: Object {x: 50.02022114840451, y: 194.40599016150796} 
  1: Object {x: 176.21168146293346, y: 186.11935655209044}
  2: Object {x: 296.82501974946393, y: 182.13051574314412}
]
]

Thanks a lot!

2

Try the following:

ExampleArray.sort((a, b) => a.y - b.y || a.x - b.x)
1 Like
3

@mootari Thanks a lot! It worked but still has some issues. Indexes are not correct order. Find my output below.

SortedArray = Array(2) [
  0:  Array(3) [
  0: Object {x: 306, y: 49.6015625}
  1:  Object {x: 173, y: 52.6015625}
  2: Object {x: 56.71095406360424, y: 60.00740978691508}
]
  1: Array(3) [
  0: Object {x: 296.82501974946393, y: 182.13051574314412}
  1: Object {x: 176.21168146293346, y: 186.11935655209044}
  2: Object {x: 50.02022114840451, y: 194.40599016150796}
]
]
4

Seems I forgot to swap x and y. I’ll leave that as an exercise to you. :slight_smile:

5

If I swap x and y, points_array.sort((a, b) => a.x - b.x || a.y - b.y), I am getting something like below, but this is not the result I’m expecting. BTW thanks a lot for your suggestions. I’m trying to tweak it a little bit.

SortedArray = Array(2) [
  0:  Array(3) [
  0: Object {x: 50.02022114840451, y: 194.40599016150796}
]
  1:  Object {x: 56.71095406360424, y: 60.00740978691508} 
  2: Object {x: 173, y: 52.6015625}
]
  1: Array(3) [
  0: Object {x: 176.21168146293346, y: 186.11935655209044} 
  1: Object {x: 296.82501974946393, y: 182.13051574314412}
  2: Object  {x: 306, y: 49.6015625}
]
6

Your array slicing aside, the order looks correct to me. I’m not sure what result you expect.

7

If I swap x and y, mostly points are sorted based on x or y, but I am expecting result should be like this (if I don’t apply slicing).

Array[6] [
  0: Object {x: 56.71095406360424, y: 60.00740978691508}  
  1: Object {x: 173, y: 52.6015625}
  2: Object {x: 306, y: 49.6015625}
  3: Object {x: 50.02022114840451, y: 194.40599016150796} 
  4: Object {x: 176.21168146293346, y: 186.11935655209044}
  5: Object {x: 296.82501974946393, y: 182.13051574314412}
]
8

We already discussed the topic at length in Organize centroid points into Array Structure - #6 by mootari where I even gave a solution for this sort of binning. Why have you created this new topic?

1 Like
9

That partially solved my issue. After slicing, the array index for the second row is just reversed. So, I am thinking about a better solution.

10

@mootari Thanks a lot! Your code helped me to solve my issue. Thanks a lot once again!