Sort 2d Array based on values

user_7894245 0
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i have a huge 2d array with the coordiantes of vertexes of hexagons. which looks like this:

let arr = [
  [150.3073578016,95.9815785601,149.1526572632,97.9815785601,150.3073578016,99.9815785601,152.6167588783,99.9815785601,153.7714594167,97.9815785601,152.6167588783,95.9815785601],
  [120.5738189383,54.4815785601,121.7285194767,54.4815785601,122.3058697459,55.4815785601,121.7285194767,56.4815785601,120.5738189383,56.4815785601,119.9964686691,55.4815785601],
  [119.9964686691,78.4815785601,122.3058697459,78.4815785601,123.4605702842,80.4815785601,122.3058697459,82.4815785601,119.9964686691,82.4815785601,118.8417681307,80.4815785601],
  [115.6663416502,100.9815785601,117.9757427269,100.9815785601,119.1304432653,102.9815785601,117.9757427269,104.9815785601,115.6663416502,104.9815785601,114.5116411118,102.9815785601],
  [124.326595688,100.9815785601,126.6359967648,100.9815785601,127.7906973032,102.9815785601,126.6359967648,104.9815785601,124.326595688,104.9815785601,123.1718951496,102.9815785601],
];

a hexagon has 6 vertexes. each subarray is a hexagon and has the x and y coordiantes of each vertex point.

so each sub-array contains 12 values.

Note: Not all hexagons have the same size!

structured like this (UNSORTED!): [x,y,x,y,x,y,x,y,x,y,x,y];

My problem now is: how can I sort the 2d array so that i have it ordered row-wise, going from top-left to bottom-right? enter image description here

My idea was to just sum each sub value, but it doesn't give me the order that i want.

function sortHexagons(hexCoordinates) {
  function sort(arr) {
    const reducer = (accumulator, currentValue) => accumulator + currentValue;
    return arr.reduce(reducer);
  }
  hexCoordinates.sort((a, b) => sort(a) - sort(b));
}
sorting arrays javascript
2 Answers

Here is an untested attempt. I average the x and y values of each hexagon, then order first by y descending, and second by x ascending. Makes assumptions about the uniformity of your hexagons.

    var arr = [
    [150.3073578016,95.9815785601,149.1526572632,97.9815785601,150.3073578016,99.9815785601,152.6167588783,99.9815785601,153.7714594167,97.9815785601,152.6167588783,95.9815785601],
    [120.5738189383,54.4815785601,121.7285194767,54.4815785601,122.3058697459,55.4815785601,121.7285194767,56.4815785601,120.5738189383,56.4815785601,119.9964686691,55.4815785601],
    [119.9964686691,78.4815785601,122.3058697459,78.4815785601,123.4605702842,80.4815785601,122.3058697459,82.4815785601,119.9964686691,82.4815785601,118.8417681307,80.4815785601],
    [115.6663416502,100.9815785601,117.9757427269,100.9815785601,119.1304432653,102.9815785601,117.9757427269,104.9815785601,115.6663416502,104.9815785601,114.5116411118,102.9815785601],
    [124.326595688,100.9815785601,126.6359967648,100.9815785601,127.7906973032,102.9815785601,126.6359967648,104.9815785601,124.326595688,104.9815785601,123.1718951496,102.9815785601],
  ];

// get the average x and y values of each array
var averageTracker = []
for (let x = 0; x < arr.length; x++) {
    var xSum = 0;
    var ySum = 0;
    for (let y = 0; y < arr[x].length; y++) {
        if (y % 2 == 0) {
            xSum = xSum + arr[x][y];
        } else {
            ySum = ySum + arr[x][y];
        }
    }
    // save the average x and y value of a hexagon against the index of the hexagon
    var indexTracker = {
        arrayPosition: x,
        xAverage: xSum / (arr[x].length / 2),
        yAverage: ySum / (arr[x].length / 2),
    };
    averageTracker.push(indexTracker);
}

// sort the hexagons by y descending, followed by x ascending
averageTracker.sort(function (a, b) {
    return b.yAverage - a.yAverage || a.xAverage - b.xAverage;
});

// get the hexagon out of the original array by index
var newArr = [];
for (let x = 0; x < averageTracker.length; x++) {
    newArr.push(arr[averageTracker[x].arrayPosition]);
}
user_84566080

If you are using this as plain javascript you need to add CDN for lodash library or you are using javascript framework and library you need to install lodash

$ yarn add lodash / npm install lodash

on the current page or component use lodash using

const _ = require('lodash'); or import * as _ from 'lodash';

you are good to go

const coordinatesArray = _.map(arr, (row) => {
  // convert every row element into chank of two element
  const coordinates = _.chunk(row, 2)
  // convert coordinates into readable form using x and y axis
  return _.map(coordinates, (i) => ({ x: i[0], y: i[1] }))
})
const sortedCoordinates = _.map(coordinatesArray, (row) => {
  // sort array based on x axis you can change ASC DESC
  return _.sortBy(row, 'x')
})
const sortHexagons = _.map(sortedCoordinates, (row) => {
  const newrow = []
  // deconstruct corrdinated into array of array form to get desicre result
  _.map(row, (i) => {
    // deconstruction on coordination
    newrow.push(i.x)
    newrow.push(i.y)
  })
  return newrow
})
// required result 
console.log(sortHexagons)
user_108934840
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