JavaScript中多个数组的笛卡尔积
我们需要编写一个包含多个数字数组的JavaScript函数。该函数应返回所有数组中元素的笛卡尔积的数组。
例如-
如果输入数组是-
[1, 2], [10, 20], [100, 200, 300]
那么输出应该是-
const output = [ [ 1, 10, 100 ], [ 1, 10, 200 ], [ 1, 10, 300 ], [ 1, 20, 100 ], [ 1, 20, 200 ], [ 1, 20, 300 ], [ 2, 10, 100 ], [ 2, 10, 200 ], [ 2, 10, 300 ], [ 2, 20, 100 ], [ 2, 20, 200 ], [ 2, 20, 300 ] ];
示例
const arr1 = [1, 2];
const arr2 = [10, 20];
const arr3 = [100, 200, 300];
const cartesianProduct = (...arr) => {
return arr.reduce((acc,val) => {
return acc.map(el => {
return val.map(element => {
return el.concat([element]);
});
}).reduce((acc,val) => acc.concat(val) ,[]);
}, [[]]);
};
console.log(cartesianProduct(arr1, arr2, arr3));输出结果
这将产生以下输出-
[ [ 1, 10, 100 ], [ 1, 10, 200 ], [ 1, 10, 300 ], [ 1, 20, 100 ], [ 1, 20, 200 ], [ 1, 20, 300 ], [ 2, 10, 100 ], [ 2, 10, 200 ], [ 2, 10, 300 ], [ 2, 20, 100 ], [ 2, 20, 200 ], [ 2, 20, 300 ] ]