1 將一個(gè)一維對(duì)象數(shù)組，根據(jù)相同的屬性值，轉(zhuǎn)化成一個(gè)二維數(shù)組
如
// 待轉(zhuǎn)換的一維數(shù)組
var arrayFirst = [{
code: 1,
datas: 'a網(wǎng)吧'
},
{
code: 1,
datas: 'b網(wǎng)吧'
}, {
code: 2,
datas: 'a酒店'
},
{
code: 2,
datas: 'b酒店'
},
{
code: 3,
datas: 'a學(xué)校'
}, {
code: 3,
datas: 'b學(xué)校'
},
{
code: 3,
datas: 'c學(xué)校'
}
]
按照相同的code值轉(zhuǎn)換成二維數(shù)組
// 轉(zhuǎn)換后的二維數(shù)組
[
[{code: 1, datas: "a網(wǎng)吧"},{code: 1, datas: "b網(wǎng)吧"}],
[{code: 2, datas: "a酒店"},{code: 2, datas: "b酒店"}],
[{code: 3, datas: "a學(xué)校"},{code: 3, datas: "b學(xué)校"},{code: 3, datas: "c學(xué)校"}]]
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es6的方法
使用es6的方法
Object.values() //返回 值 數(shù)組
返回?cái)?shù)組，成員是參數(shù)對(duì)象自身的（不含繼承的）所有可遍歷(enumerable)屬性的鍵值
// 轉(zhuǎn)換后的二維數(shù)組
var arrayTwo = Object.values(arrayFirst.reduce((res, item) => {
res[item.code] ? res[item.code].push(item) : res[item.code] = [item];
return res;
}, {}));
console.log(arrayTwo)
第二種方法
/ 轉(zhuǎn)換后的二維數(shù)組
function convert (arr) {
var map1 = {};
while(arr.length) {
let current = arr.pop(); // 會(huì)影響原數(shù)組
map1[current.code] = map1[current.code] || [];
map1[current.code].push(current);
}
return Object.keys(map1).map(key => map1[key]);
}
var arrayTwo = convert(arrayFirst)
console.log(arrayTwo)
2 以上是一個(gè)具有相同code值的一維數(shù)組，需要轉(zhuǎn)換成如下的二維數(shù)組
let arr = [
{code: "China", name: "xiaohuai"},
{code: "Africa", name: "neiLuoBi"},
{code: "Asia", name: "hanGuo"},
{code: "China", name: "tnnyang"},
{code: "Africa", name: "nanFei"},
{code: "China", name: "yangMan"}
]
var map = new Map();
var newArr = [];
arr.forEach(item => {
map.has(item.code) ? map.get(item.code).push(item) : map.set(item.code, [item]);
})
newArr = [...map.values()];
console.log(newArr);
實(shí)現(xiàn)了一維數(shù)組轉(zhuǎn)二維，那么再將轉(zhuǎn)換后的二維數(shù)組轉(zhuǎn)換為一維數(shù)組呢？還是直接上代碼吧：
let arr = [
[ {code: "China", name: "xiaohuai"}, {code: "China", name: "tnnyang"}, {code: "China", name: "yangMan"} ],
[ {code: "Africa", name: "neiLuoBi"}, {code: "Africa", name: "nanFei"} ],
[ {code: "Asia", name: "hanGuo"} ]
]
//方法一：
function reduceDimension(arr) {
var reduced = [];
for (var i = 0; i < arr.length; i++) {
for (var j = 0; j < arr[i].length; j++) {
reduced.push(arr[i][j]);
}
}
return reduced;
}
console.log(reduceDimension(arr));
//方法二：
console.log([].concat.apply([], arr));
