生成完整（所有大小）的数组组合

Question

如何生成多个数组的完全组合？

const source = [ ["a", "b", "c"], ["d", "e", "f"], ["g", "h", "i"] ];
const result = combination(source);

需要结果，如笛卡尔积，但具有所有大小的组合：

["a"]
["a", "d"]
["a", "d", "g"]
...
["b"]
...
["b", "f", "i"]
...
["i"]

Answer 1

这个怎么样：

function cartesianProduct(arrArr) {
  if (arrArr.length === 0) return [];

  const [firstArr, ...restArrs] = arrArr;
  const partialProducts = cartesianProduct(restArrs || []);

  let ret = firstArr.map(elem => [elem]);
  ret = ret.concat(partialProducts);
  ret = ret.concat(partialProducts.reduce((acc, product) => {
    return acc.concat(firstArr.map(elem => [elem].concat(product)));
  }, []));

  return ret;
}

生成完整（所有大小）的数组组合

Generating full (all sizes) combinations of arrays

javascript

combinations

cartesian-product