根据元素的数字顺序合并两个数组

Question

I try to came up to algorithm for parsing array. What it should do: in input in takes two arrays first_array=[[10,25], [30,45], [50,60]] and second_array=[35, 40] in output it should return one array [[10,25], [30,35], [40,45], [50,60]] . As you guessed it takes second_array[1] and compare with first_array[each][1] and creates subarray. So far I got (Code Below). Some how in if statement I need two returning. Second argument also could be a multiple array.

 /*---- First part of problem ----*/ const first_array=[[10,25], [30,45], [50,60]]; const second_array=[35, 40]; const result = first_array.map(record => { if (second_array[0] > record[0] && second_array[0] < record[1]) { return [[record[0], second_array[0]], [second_array[1], record[1]]] } else { return record } }); console.log(result) // result [ [10,25] , [[30,35],[40,45]] , [50,60] ] // expect [ [10,25] , [30,35] , [40,45] , [50,60] ] /*---- Second part of problem ----*/ const first_array=[15, 60]; const second_array=[[25,30], [30,40], [45,55]]; // [[15, 60]] // [[15, 25], [30, 60]] // [[15, 25], [30, 30], [40, 60]] //output// [[15, 25], [30, 30], [40, 45], [55, 60]] 

Answer 1

first I join the arrays and after that sorted and split them

var a=[[10,25], [30,45], [50,60]]
var b=[35, 40];

var sorted=[].concat.apply([], a,b).sort();

var pairs = [];

for(var i = 0; i < sorted.length; i += 2)
{
    pairs.push(sorted.slice(i, i + 2));
}

Answer 2

You could use a Generator for the arrays and take the same generator for nested arrays.

Then check if the values are in order and update the result array by checking the lenght of the collector array.

Proceed until both generators return done .

 function combine(leftArray, rightArray) { function* getElements(array) { var i = 0; while (i < array.length) { if (Array.isArray(array[i])) { yield* getElements(array[i]) } else { yield array[i]; } i++; } } function update(value) { temp.push(value); if (temp.length === 2) { result.push(temp); temp = []; } } var left = getElements(leftArray), right = getElements(rightArray), l = left.next(), r = right.next(), temp = [], result = []; while (!l.done || !r.done) { if (r.done || !l.done && l.value < r.value) { update(l.value); l = left.next(); continue; } if (l.done || !r.done && r.value < l.value) { update(r.value); r = right.next(); } } if (temp.length) { result.push(temp); } return result; } console.log(combine([[10, 25], [30, 45], [50, 60]], [[12, 42], [67, 69]])); 

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Foor unsorted arrays, you could flat the arrays, sort and group them.

 function combine(left, right) { const flat = (r, a) => Array.isArray(a) ? a.reduce(flat, r) : [...r, a]; return [left, right] .reduce(flat, []) .sort((a, b) => a - b) .reduce((r, a, i) => (i & 1 ? r[r.length - 1].push(a) : r.push([a]), r), []); } console.log(combine([[20, 19], [30, 45], [9, 5]], [[12, 42], [67, 69]])); 

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Answer 3

Here is an interesting approach which i expect to be fast.

We have an array scaner function function which works like a map. Takes a function which modifies each element while updating an accumulator which is kept under closure. The function we use here is a sorter which takes to size 2 arrays and order the smallest items in one and the rest in the other. So sorter([1,5], [3,7]) will result [1,3] and accumulator will change to [5,7] . Here it is;

 var first_array = [[10,25], [30,45], [50,60]], second_array = [28,46], merger = (a,f,t) => a.map((t => e => f(e,t))(t)).concat([t]), sorter = (a,b) => a[1] < b[1] ? a[1] < b[0] ? a : a[0] < b[0] ? ([a[1],b[0]] = [b[0],a[1]], a) : ([a[1],b[0]] = [b[0],a[1]], a.reverse()) : a[0] > b[1] ? ([a[0],b[0]] = [b[0],a[0]], [a[1],b[1]] = [b[1],a[1]], a) : a[0] > b[0] ? ([a[0],b[1]] = [b[1],a[0]], [a[0],b[0]] = [b[0],a[0]], [a[1],b[1]] = [b[1],a[1]], a) : ([a[1],b[0]] = [b[0],a[1]], b.reverse(), a), result = merger(first_array,sorter,second_array); console.log(JSON.stringify(result)); 

Answer 4

Use reduce instead of map

const first_array=[[10,25], [30,45], [50,60]];
const second_array=[35, 40];

const result = first_array.reduce((a, record) => {
  if (second_array[0] > record[0] && second_array[0] < record[1]) {
    a.push([record[0], second_array[0]])
    a.push([second_array[1], record[1]])
  } else {
    a.push(record)
  }

  return a
}, [])

console.log(result)