JavaScript：根据排列顺序对数组进行排序？

Question

I have a list of N elements with an array of three colors like this:

[
  { id: 1, colors: ['Red', 'Blue', 'White'] },
  { id: 2, colors: ['Red', 'Blue', 'Blue'] },
  { id: 3, colors: ['Red', 'Red', 'White'] },
  { id: 4, colors: ['Red', 'Red', 'Red'] }
]

And I would like to sort them based on this priority order, for example:

[Red,Red,Red]
[Red,Red,X]
[Red,X,Red]
[Red,X,X]
[X,Red,Red]
[X,Red,X]
[X,X,Red]

Where the 'X' indicates any other color that is not the one I indicate, in this example is 'Red'.

So an expected output, for this example would be:

[
  { id: 1, colors: ['Red', 'Red', 'Red'] },
  { id: 2, colors: ['Red', 'Red', 'White'] },
  { id: 3, colors: ['Red', 'Blue', 'White'] },
  { id: 4, colors: ['Red', 'Blue', 'Blue'] }
]

Any idea on how to approach this?

I tried finding the duplicates and sorting the parent array based on the colors, but I need to take into consideration the priority order.

elements.sort((a, b) => {
  const colorDupsA = findDuplicates(a.colors);
  const colorDupsB = findDuplicates(b.colors);
  return colorDupsB.length - colorDupsA.length;
});

Answer 1

Or, using an index array srt you can do it in the following way:

 const arr=[ {id: 1,colors: ['Red', 'Blue', 'White']}, {id: 1,colors: ['Red', 'Blue', 'Blue']}, {id: 1,colors: ['Red', 'Red', 'White']}, {id: 1,colors: ['Red', 'Red', 'Red']}]; const srt=arr.map((e,i)=>[i,e.colors.map(c=>c=="Red"?"1":"0").join("")]) console.log(srt.sort((a,b)=>b[1]-a[1]).map(([i])=>arr[i]));

You can even reduce it to a one-liner:

arr.map((e,i)=>[i,e.colors.map(c=>c=="Red"?"1":"0").join("")])
   .sort((a,b)=>b[1]-a[1]).map(([i])=>arr[i])

Answer 2

So you need to loop over the arrays and figure out if the one is red and the other. If they both or or both are not, then you move to the next and check.

 const data = [ { colors: ['Blue', 'Blue', 'Red'] }, { colors: ['Blue', 'Red', 'White'] }, { colors: ['Blue', 'Blue', 'White'] }, { colors: ['Red', 'Blue', 'White'] }, { colors: ['Red', 'Blue', 'Blue'] }, { colors: ['Red', 'Red', 'White'] }, { colors: ['Red', 'Red', 'Red'] } ]; data.sort((a,b) => { const ac = a.colors; const bc = b.colors for (let i=0; i<ac.length; i++){ const check = (ac[i] === bc[i]) || (ac[i];== 'Red' && bc[i];== 'Red')? if (check) continue: return ac[i] === 'Red'; -1; 1; } return 0. }); console.log(data);

If you have to do sorting based on the other colors, generating a "weighted value" for the array would be a way to go

 const data = [ { colors: ['Blue', 'Blue', 'Red'] }, { colors: ['Blue', 'Red', 'White'] }, { colors: ['Blue', 'Blue', 'White'] }, { colors: ['Red', 'Blue', 'White'] }, { colors: ['Red', 'Blue', 'Blue'] }, { colors: ['Red', 'Red', 'White'] }, { colors: ['Red', 'Red', 'Red'] } ]; const values = { Red: 3, Blue: 2, White: 1, }; const weight = arr => +arr.map(c => values[c] || 0).reverse().join(""); data.sort((a, b) => weight(b.colors) - weight(a.colors)); console.log(data);

Answer 3

Here is a possible solution:

1. Create a private function getColorScore to calculate the score of a colors array according to the occurrences of your color and its indices in it. This can be done using .reduce
2. Sort the array of objects using this function, where the object with the greater score for its colors list, would be first. This is done using .sort

 const arr = [ { id: 1, colors: ['Red', 'Blue', 'White'] }, { id: 1, colors: ['Red', 'Blue', 'Blue'] }, { id: 1, colors: ['Red', 'Red', 'White'] }, { id: 1, colors: ['Red', 'Red', 'Red'] } ]; const getColorScore = (colors, color) => colors.reduce((acc,item,index) => { acc += item===color? colors.length-index: 0; return acc; }, 0); const sortArrayByColor = (arr,color) => arr.sort((a,b) => getColorScore(b.colors,color)-getColorScore(a.colors,color)) console.log( sortArrayByColor(arr,'Red') );

Answer 4

In the sort method, Calculate the value for each object based on permutation order and compare values.

 const data = [ { colors: ["Blue", "Blue", "Red"] }, { colors: ["Blue", "Red", "White"] }, { colors: ["Blue", "Blue", "White"] }, { colors: ["Red", "Blue", "White"] }, { colors: ["Red", "Blue", "Blue"] }, { colors: ["Red", "Red", "White"] }, { colors: ["Red", "Red", "Red"] }, ]; const getValue = (obj) => obj.colors.reduce((acc, cur) => +(cur === "Red") + acc * 10, 0); data.sort((a, b) => getValue(b) - getValue(a)); console.log(data);