js实现数组分组

有这样一个数组：

[‘法国’,’澳大利亚’,’智利’,’新西兰’,’西班牙’,’加拿大’,’阿根廷’,’美国’,’0’,’国产’,’波多黎各’,’英国’,’比利时’,’德国’,’意大利’,’意大利’,]

现在希望让每3个分成一个数组，像这样：

[[‘法国’,’澳大利亚’,’智利’],[‘新西兰’,’西班牙’,’加拿大’],[‘阿根廷’,’美国’,’0’],[‘国产’,’波多黎各’,’英国’],[‘比利时’,’德国’,’意大利’],[‘意大利’],]

实现办法

第一种办法：

 var data = ["法国","澳大利亚","智利","新西兰","西班牙","加拿大","阿根廷","美国","0","国产","波多黎各","英国","比利时","德国","意大利","意大利",];
var result = [];
for(var i=0,len=data.length;i<len;i+=3){
   result.push(data.slice(i,i+3));
}

第二种办法：

var countries= ["法国","澳大利亚","智利","新西兰","西班牙","加拿大","阿根廷","美国","0","国产","波多黎各","英国","比利时","德国","意大利","意大利"];
var chunkCountries =  _.chunk(countries,3);

使用lodash的chunk方法，如果不想使用整个类库，可以单独引入这个方法

import chunk from "lodash/chunk";
var chunk =require("lodash/chunk");

如果你只想用引入的chunk，用这个：https://github.com/ryancole/chunk/blob/master/src/chunk.js

第三种办法：

var arr = ["法国","澳大利亚","智利","新西兰","西班牙","加拿大","阿根廷","美国","0","国产","波多黎各","英国","比利时","德国","意大利","意大利"],
    newArr = [],
    b;
arr.forEach(function(item, index, array) {
    var a = Math.floor(index / 3);
    if (b !== a) {
        b = a;
        newArr[a] = new Array();
    }
    newArr[a].push(item);         
});

第四种办法：

function group(array, subGroupLength) {
    var index = 0;
    var newArray = [];

    while(index < array.length) {
        newArray.push(array.slice(index, index += subGroupLength));
    }

    return newArray;
}

var countries = ["法国","澳大利亚","智利","新西兰","西班牙","加拿大","阿根廷","美国","0","国产","波多黎各","英国","比利时","德国","意大利","意大利",];
var groupedCountries = group(countries, 3);

第五种办法：

var a = ["法国","澳大利亚","智利","新西兰","西班牙","加拿大","阿根廷","美国","0","国产","波多黎各","英国","比利时","德国","意大利","意大利"];
var b = [];
var result = [];
var k = 0;

for(var i = 0; i<a.length; ++i){
    if(i%3 == 0){
        b = [];
        for(var j = 0; j<3; ++j){
            if(a[i+j] == undefined){
                continue;
            } else{
                b[j] = a[i+j];
            }
        }
        result[k] = b;
        k++;
    }

}
console.log(result);

第六种办法：

var chunk = function(arr, num){
      num = num*1 || 1;
      var ret = [];
      arr.forEach(function(item, i){
        if(i % num === 0){
          ret.push([]);
        }
        ret[ret.length - 1].push(item);
      });
      console.log(ret);
      return ret;
    };
// run
var source = ["法国","澳大利亚","智利","新西兰","西班牙","加拿大","阿根廷","美国","0","国产","波多黎各","英国","比利时","德国","意大利","意大利"];
chunk(source, 3);

第七种办法：

var arr = ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j"];

function formatArray(arr) {

var begin = 0,
    end = begin + 3;
var result = [],
    arrLength = arr.length;

if (end >= arrLength) return result.push(arr);

while (end < arrLength) {

    result.push(arr.slice(begin, end));

    begin = begin + 3;
    end = begin + 3;
    if (end > arrLength) {
        end = arrLength;
        result.push(arr.slice(begin, end));
        break;
    }
}

return result;

}

formatArray(arr); // [["a", "b", "c"], ["d", "e", "f"], ["g", "h", "i"], ["j"]]

2016年4月19日 新增 数组合并方法：

var list = [
    ["11","22","33"],
    ["aa","bb"],
]

//最终的结果是
var list = [
   ["112233"],
   ["aabb"]
]
//方法一
var list=list.map(function (v) {
    return new Array(v.join(""))
})
//方法二
var res = []
for(i in list) {
    res.push(list[i].toString().replace(/,/g, ""))
}
//方法三
var result = [];
for(var i = 0, k = list.length; i < k; i++){
    result.push(list[i].join("").split());
}

以上办法由以下大神指导，感谢！

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