将两个多维数组合并为带有对象的多维数组

Question

I'm learning the new JavaScript ES6 syntax and am trying to create a multidimensional array with objects from 2 other multidimensional arrays. Presumably my syntax is incorrect, but I don't know how to fix it. The result should be:

[
  [{    letter: w,    instances: 1
  }, {  letter: o,    instances: 1
  }, {  letter: d,    instances: 2
  }, {  letter: r,    instances: 1
  }],
  [{    letter: s,    instances: 1
  }, {  letter: y,    instances: 1
  }],
  [{    letter: h,    instances: 1
  }, {  letter: e,    instances: 1
  }, {  letter: l,    instances: 2
  }, {  letter: o,    instances: 1
  }]
]

My code uses two map methods:

 var letters = [ ["w", "o", "d", "r"], ["s", "y"], ["h", "e", "l", "o"] ]; var numbers = [ [1, 1, 2, 1], [1, 1][1, 1, 2, 1] ]; var objArr = letters.map(function(c, i) { return c.map(function(c2, i2, a2) { return { letter: c2, instances: numbers[i] } }) }); console.log(objArr); 

It correctly returns a multidimensional array with objects and correct letter values, but the number values are incorrect. Can anyone find why this happens? Also, does anyone think there's a better way of storing the letters and the number of numbers?

Answer 1

One very small mistake in instances: Pls see below

 var letters = [["w", "o", "d", "r"],["s", "y"],["h", "e", "l", "o"]]; var numbers = [[1,1,2,1],[1,1], [1,1,2,1]]; var objArr = letters.map(function(c,i) { return c.map(function(c2,i2) { return {letter: c2, instances: numbers[i][i2]} }) }); console.log(objArr) 

Answer 2

Since you have a two-dimensional array, you need to use two indexes to access it. Use the first index i , to access the inner array and the use second index j , to access the number inside the array.

 let letters = [["w", "o", "d", "r"],["s", "y"],["h", "e", "l", "o"]], numbers = [[1, 1, 2, 1],[1, 1],[1, 1, 2, 1]], result = letters.map((arr, i) => arr.map((letter, j) => ({letter,instances: numbers[i][j]}))); console.log(result);