以某种方式（从右到左）合并、扁平化和连接 javascript 中的多个多维数组的任何简单方法？

Question

我需要一种简单的方法来以某种方式（从右到左）javascript 合并、扁平化和连接多个多维数组

# Exemple
[['.class1', '.class2'], ['.class3', ['.class4', '.class5', ...], ['.class6'], ...]]
# OR
[['.class1', '.class2'], ['.class3', ['.class4', '.class5', ...]], ['.class6'], ...]

# Would become
['.class1.class3.class4.class6', '.class1.class3.class5.class6', '.class2.class3.class4.class6', '.class2.class3.class5.class6', ...]

我从 underscore.js 库中找到了 reduceRight 函数，但我不确定如何轻松实现它，因为它需要递归完成。

Answer 1

对于 Array#forEach.

的可变长度部分，您可以使用迭代和递归方法

此版本现在可以使用嵌套数组并在高级中将其扁平化。

function combine(array) {
    function c(part, index) {
        var temp = array[index];

        if (Array.isArray(temp) && temp.some(function (a) { return Array.isArray(a); })) {
            temp = combine(array[index].map(function (a) { return Array.isArray(a) ? a : [a]; }));
        }
        temp.forEach(function (a) {
            var p = part.concat(a);
            if (p.length === array.length) {
                r.push(p.join(''));
                return;
            }
            c(p, index + 1);
        });
    }

    var r = [];

    c([], 0);
    return r;
}

var array = [
        ['.class1', '.class2'],
        ['.class3',
            ['.class4', '.class5'],
            ['.class6']
        ]
    ],
    result = combine(array);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 2

如果您愿意在多维数组的每个元素上使用 lodash, which is a better version of underscore (imo), this can be expressed fairly simply using flattenDeep (https://lodash.com/docs/4.17.4#flattenDeep):

function combine(list) {
  const arrays = list.map(_.flattenDeep);
  return arrays.map((a) => a.join('');
}

Answer 3

var data = [['.class1', '.class2'], ['.class3', ['.class4', '.class5'], ['.class6']]];

function cartesian(a, b) {                                  // return the cartesian product of the two arrays a and b
  if(!a.length) return b;                                   // if a is empty then the result of the product is b
  if(!b.length) return a;                                   // if b is empty then the product is a
  
  return a.reduce((res, ae) => (b.forEach(be => res.push(ae + be)), res), []); // product of non-empty a and non-empty b
}

function combos(arr) {                                      // take an array arr and return the combinations out from its nested arrays
  if(arr.every(e => !Array.isArray(e))) return arr;         // if the array doesn't contain any nested arrays then return it as it is

  return arr.reduce((acc, e) => {                           // otherwise return the cartesian product of all its elements
    e = Array.isArray(e)? combos(e): [e];                   // if the current element is an array, then get its combos, otherwise, wrap it in an array
    return cartesian(acc, e);                               // get the cartesian product of previous elements and the combos of this element e
  }, []);
}

console.log(combos(data));

以某种方式（从右到左）合并、扁平化和连接 javascript 中的多个多维数组的任何简单方法？

Any easy way to merge, flattern and concat multiple multi-dimensional arrays in javascript in a certain way (right to left)?

javascript

arrays

jquery

multidimensional-array

underscore.js