根据变量javascript对数组项进行分组

Question

我有一个从xml文档动态创建的数组，看起来像这样:

myArray[0] = [1,The Melting Pot,A]
myArray[1] = [5,Mama's MexicanKitchen,C]
myArray[2] = [6,Wingdome,D]
myArray[3] = [7,Piroshky Piroshky,D]
myArray[4] = [4,Crab Pot,F]
myArray[5] = [2,Ipanema Grill,G]
myArray[6] = [0,Pan Africa Market,Z]

该数组在for循环中创建，可以包含基于xml文档

的任何内容。

我需要完成的是根据字母对数组中的项进行分组这样所有包含字母A的数组对象就会以

的形式存储在另一个数组中

other['A'] = ['item 1', 'item 2', 'item 3'];
other['B'] = ['item 4', 'item 5'];
other['C'] = ['item 6'];

为了澄清，我需要根据数组内的变量对项进行排序，在本例中是字母，以便所有包含字母A的数组对象都通过字母

进入新数组。

谢谢你的帮助!

Answer 1

不应该使用索引为非整数的数组。您的other变量应该是一个普通对象，而不是一个数组。(它可以处理数组，但不是最好的选择。)

// assume myArray is already declared and populated as per the question
var other = {},
    letter,
    i;
for (i=0; i < myArray.length; i++) {
   letter = myArray[i][2];
   // if other doesn't already have a property for the current letter
   // create it and assign it to a new empty array
   if (!(letter in other))
      other[letter] = [];
   other[letter].push(myArray[i]);
}

给定myArray中的一个项目[1，"The Melting Pot"，"A"]，您的示例并没有明确您是否要将整个事物存储在other中，或者只是在第二个数组位置的字符串字段-您的示例输出只有字符串，但它们与myArray中的字符串不匹配。我的代码最初只是通过说other[letter].push(myArray[i][1]);来存储字符串部分，但是一些匿名的人编辑了我的帖子，将其更改为other[letter].push(myArray[i]);，其中存储了所有[1，"熔炉"，"A"]。我已经给了您所需的基本代码，您可以自己决定要在这里做什么。

Answer 2

试试http://underscorejs.org/#groupBy提供的groupBy函数

_.groupBy([1.3, 2.1, 2.4], function(num){ return Math.floor(num); });
Result => {1: [1.3], 2: [2.1, 2.4]}

Answer 3

您必须创建一个空JavaScript对象，并为每个字母分配一个数组。

var object = {};
for ( var x = 0; x < myArray.length; x++ )
{
    var letter = myArray[x][2];
    // create array for this letter if it doesn't exist
    if ( ! object[letter] )
    {
        object[letter] = [];
    }
    object[ myArray[x][2] ].push[ myArray[x] ];
}

Answer 4

此代码将适用于您的example。

var other = Object.create(null),  // you can safely use in opeator.
    letter,
    item,
    max,
    i;
for (i = 0, max = myArray.length; i < max; i += 1) {
   item = myArray[i];
   letter = myArray[2];
   // If the letter does not exist in the other dict,
   // create its items list
   other[letter] = other[letter] || [];
   other.push(item);
}

Answer 5

Good ol' ES5 Array .

var other = {};
myArray.forEach(function(n, i, ary){
    other[n[2]] = n.slice(0,2);
});

Answer 6

Try -

var myArray = new Array();
myArray[0] = [1,"The Melting Pot,A,3,Sake House","B"];
myArray[1] = [5,"Mama's MexicanKitchen","C"];
myArray[2] = [6,"Wingdome","D"];
myArray[3] = [7,"Piroshky Piroshky","D"];
myArray[4] = [4,"Crab Pot","F"];
myArray[5] = [2,"Ipanema Grill","G"];
myArray[6] = [0,"Pan Africa Market","Z"];
var map = new Object();
for(i =0 ; i < myArray.length; i++){
    var key = myArray[i][2];
    if(!map[key]){
       var array = new Array();        
        map[key] = array;
    }
    map[key].push(myArray[i]);
}