我需要根据N个属性列表生成一组完整的变体,同时保持属性名称不变。
I need to generate a complete set of variants based on a list of N attributes, while keeping the attribute name intact.
var input = [ { 'colour' : ['red', 'green'] }, { 'material' : ['cotton', 'wool', 'silk'] }, { 'shape' : ['round', 'square', 'rectangle'] } ]; var expected = [ { 'colour': 'red', 'material': 'cotton', 'shape': 'round' }, { 'colour': 'red', 'material': 'cotton', 'shape': 'square' }, { 'colour': 'red', 'material': 'cotton', 'shape': 'rectangle' }, { 'colour': 'red', 'material': 'wool', 'shape': 'round' }, { 'colour': 'red', 'material': 'wool', 'shape': 'square' }, { 'colour': 'red', 'material': 'wool', 'shape': 'rectangle' }, { 'colour': 'red', 'material': 'silk', 'shape': 'round' }, { 'colour': 'red', 'material': 'silk', 'shape': 'square' }, { 'colour': 'red', 'material': 'silk', 'shape': 'rectangle' }, { 'colour': 'green', 'material': 'cotton', 'shape': 'round' }, { 'colour': 'green', 'material': 'cotton', 'shape': 'square' }, { 'colour': 'green', 'material': 'cotton', 'shape': 'rectangle' }, { 'colour': 'green', 'material': 'wool', 'shape': 'round' }, { 'colour': 'green', 'material': 'wool', 'shape': 'square' }, { 'colour': 'green', 'material': 'wool', 'shape': 'rectangle' }, { 'colour': 'green', 'material': 'silk', 'shape': 'round' }, { 'colour': 'green', 'material': 'silk', 'shape': 'square' }, { 'colour': 'green', 'material': 'silk', 'shape': 'rectangle' } ];对于阵列的笛卡尔积,有很多算法,但我似乎找不到一个对于保留密钥的对象。
There are lots of algorithms around for cartesian products of arrays, but I can't seem to find one for objects that preserves the keys.
性能不是一个大问题,因为每个属性永远不会有超过十几个值。订单不必完全匹配预期。
Performance isn't a massive concern as there will never be more than a dozen or so values for each attribute. The order doesn't have to exactly match expected.
我已根据标准进行了初步尝试列表算法,但我很挣扎:
I've made an initial attempt based on the standard algorithms for lists, but I'm struggling:
function cartesianProduct(input, current) { if (!input || input.length < 1) { return []; } var head = input[0]; var tail = input.slice(1); var output = []; for (var key in head) { for (var i = 0; i < head[key].length; i++) { if (typeof current == 'undefined') { var current = {}; } current[key] = head[key][i]; var productOfTail = cartesianProduct(tail, current); output.push(current); console.log(current); } } return output; } console.log(cartesianProduct(input));推荐答案
一旦你摆脱''我'是一个全局变量问题',您可以使用以下代码获得结果:
Once you get rid of the ' 'i' is a global var issue', you can get to the result with this code for instance :
var input = [ { 'colour' : ['red', 'green'] }, { 'material' : ['cotton', 'wool', 'silk'] }, { 'shape' : ['round', 'square', 'rectangle'] } ]; function cartesianProduct(input, current) { if (!input || !input.length) { return []; } var head = input[0]; var tail = input.slice(1); var output = []; for (var key in head) { for (var i = 0; i < head[key].length; i++) { var newCurrent = copy(current); newCurrent[key] = head[key][i]; if (tail.length) { var productOfTail = cartesianProduct(tail, newCurrent); output = output.concat(productOfTail); } else output.push(newCurrent); } } return output; } function copy(obj) { var res = {}; for (var p in obj) res[p] = obj[p]; return res; } console.log(cartesianProduct(input));更多推荐
javascript中对象的笛卡尔积
发布评论