如何排序多个字段对象的数组？ [英] How to sort an array of objects by multiple fields?

问题描述

从这个原来的问题，我将如何应用排序对多个字段？

From this original question, how would I apply a sort on multiple fields?

使用这个稍微适应的结构，我将如何排序城市（升序）及那么价格（降序）？

Using this slightly adapted structure, how would I sort city (ascending) & then price (descending)?

var homes = [
    {"h_id":"3",
     "city":"Dallas",
     "state":"TX",
     "zip":"75201",
     "price":"162500"},
    {"h_id":"4",
     "city":"Bevery Hills",
     "state":"CA",
     "zip":"90210",
     "price":"319250"},
    {"h_id":"6",
     "city":"Dallas",
     "state":"TX",
     "zip":"75000",
     "price":"556699"},
    {"h_id":"5",
     "city":"New York",
     "state":"NY",
     "zip":"00010",
     "price":"962500"}
    ];

我喜欢的其实不是一个回答给予它提供了一个通用的方法。我在哪里打算使用此code，我将不得不排序日期以及其他的东西。有能力的黄金的对象似乎得心应手，如果没有一点累赘。

I liked the fact than an answer was given which provided a general approach. Where I plan to use this code, I will have to sort dates as well as other things. The ability to "prime" the object seemed handy, if not a little cumbersome.

我试图建立这个<一个href=\"http://stackoverflow.com/questions/3230028/how-to-order-a-json-object-by-two-keys/3230748#3230748\">answer进入一个很好的通用示例，但我没有多少运气。

I've tried to build this answer into a nice generic example, but I'm not having much luck.

推荐答案

一个多维的排序方法，的在此基础上回答：

A multi dimensional sorting method, based on this answer:

更新：这是一个优化的版本。它可以做更多的preprocessing，并为每一个事先排序选项进行比较的功能。它可能需要更多的内存（因为它存储每个排序选项的功能，但它应该preform好一点，因为它不具备比较期间，以确定正确的设置。我没有做任何分析，虽然

Update: Here is an "optimized" version. It does a lot more preprocessing and creates a comparison function for each sorting option beforehand. It might need more more memory (as it stores a function for each sorting option, but it should preform a bit better as it does not have to determine the correct settings during the comparison. I have not done any profiling though.

var sort_by;

(function() {
    // utility functions
    var default_cmp = function(a, b) {
            if (a == b) return 0;
            return a < b ? -1 : 1;
        },
        getCmpFunc = function(primer, reverse) {
            var dfc = default_cmp, // closer in scope
                cmp = default_cmp;
            if (primer) {
                cmp = function(a, b) {
                    return dfc(primer(a), primer(b));
                };
            }
            if (reverse) {
                return function(a, b) {
                    return -1 * cmp(a, b);
                };
            }
            return cmp;
        };

    // actual implementation
    sort_by = function() {
        var fields = [],
            n_fields = arguments.length,
            field, name, reverse, cmp;

        // preprocess sorting options
        for (var i = 0; i < n_fields; i++) {
            field = arguments[i];
            if (typeof field === 'string') {
                name = field;
                cmp = default_cmp;
            }
            else {
                name = field.name;
                cmp = getCmpFunc(field.primer, field.reverse);
            }
            fields.push({
                name: name,
                cmp: cmp
            });
        }

        // final comparison function
        return function(A, B) {
            var a, b, name, result;
            for (var i = 0; i < n_fields; i++) {
                result = 0;
                field = fields[i];
                name = field.name;

                result = field.cmp(A[name], B[name]);
                if (result !== 0) break;
            }
            return result;
        }
    }
}());

实例：

homes.sort(sort_by('city', {name:'price', primer: parseInt, reverse: true}));

DEMO

原有的功能：

var sort_by = function() {
   var fields = [].slice.call(arguments),
       n_fields = fields.length;

   return function(A,B) {
       var a, b, field, key, primer, reverse, result, i;

       for(i = 0; i < n_fields; i++) {
           result = 0;
           field = fields[i];

           key = typeof field === 'string' ? field : field.name;

           a = A[key];
           b = B[key];

           if (typeof field.primer  !== 'undefined'){
               a = field.primer(a);
               b = field.primer(b);
           }

           reverse = (field.reverse) ? -1 : 1;

           if (a<b) result = reverse * -1;
           if (a>b) result = reverse * 1;
           if(result !== 0) break;
       }
       return result;
   }
};

DEMO

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