在Jquery中汇总和分组JSON对象
我在Jquery中总结和分组我的对象时遇到了问题，因为我希望按国家/地区进行分组，然后根据子期间4,5和6对col1中的值进行总计。 col1，col2，col3是动态的，但使用它就是一个例子。
我需要的是获得存储在国家变量中的国家总数，存储在columns变量中的每个子期间的总计，以及存储在averages变量中的总计数。
这是我在jsfiddle中的代码：
http://jsfiddle.net/8vVK7/8/
我的目标：
var g_jsonData = [ { "Country": "Spain", "Year": "2000", "Subperiod": "4", "col1": "75", "col2": "500", "col3": "200" }, { "Country": "Spain", "Year": "2001", "Subperiod": "4", "col1": "50", "col2": "500", "col3": "300" }, { "Country": "Spain", "Year": "2002", "Subperiod": "4", "col1": "50", "col2": "200", "col3": "300" }, { "Country": "Spain", "Year": "2003", "Subperiod": "4", "col1": "", "col2": "200", "col3": "300" }, { "Country": "Spain", "Year": "2005", "Subperiod": "5", "col1": "125", "col2": "500", "col3": "300" }, { "Country": "Spain", "Year": "2012", "Subperiod": "6", "col1": "100.75", "col2": "500", "col3": "200" }, { "Country": "Spain", "Year": "2013", "Subperiod": "6", "col1": "200", "col2": "500", "col3": "300" }, { "Country": "France", "Year": "2000", "Subperiod": "4", "col1": "100", "col2": "100", "col3": "300" }, { "Country": "France", "Year": "2001", "Subperiod": "4", "col1": "100", "col2": "100", "col3": "300" }, { "Country": "France", "Year": "2002", "Subperiod": "4", "col1": "100", "col2": "200", "col3": "300" }, { "Country": "France", "Year": "2005", "Subperiod": "5", "col1": "100", "col2": "200", "col3": "300" }, { "Country": "France", "Year": "2012", "Subperiod": "6", "col1": "100", "col2": "100", "col3": "300" }, { "Country": "France", "Year": "2013", "Subperiod": "6", "col1": "100", "col2": "100", "col3": "300" }]; 以下是我想得到的最终结果，这是基于每个国家/地区的每个子期间的col1汇总。
countries = { "Spain":{ "4":175, "5":125, "6":300.75 }, "France":{ "4":300, "5":100, "6":200, } }
子期间4,5,6的总计应显示为：
columns = { "4":475, "5":225, "6":500.75 }
我还希望获得每个国家/地区的总计数，每个子期间：
averages = { "Spain":{ "4":3, "5":1, "6":2 }, "France":{ "4":3, "5":1, "6":2 } }
我想尽可能地坚持我的代码。 谢谢，谢谢你的帮助。
这应该是诀窍：
g_jsonData.reduce(function(out, curr){ // Make sure the current country exists on the output object. // Then add the current object's col1 to the current country's subperiod, // checking to see if the current subperiod exists. Also, cast the `col1` to int `(+curr.col1)` out.countries[curr.Country] = out.countries[curr.Country] || {}; out.countries[curr.Country][curr.Subperiod] = (out.countries[curr.Country][curr.Subperiod] || 0) + (+curr.col1); // And add it to the total, too. out.columns[curr.Subperiod] = (out.columns[curr.Subperiod] || 0) + (+curr.col1); // Count occurences out.count[curr.Country] = out.count[curr.Country] || {}; out.count[curr.Country][curr.Subperiod] = (out.count[curr.Country][curr.Subperiod] || 0) + 1; return out; }, {'columns':{},'countries':{},'count':{}}); // second parameter to `reduce` is a default object, in this case: `{'columns':{},'countries':{},'count':{}}}`
返回：
{ "columns": { "4": 475, "5": 225, "6": 500.75 }, "countries": { "Spain": { "4": 175, "5": 125, "6": 300.75 }, "France": { "4": 300, "5": 100, "6": 200 } }, "count": { "Spain": { "4": 3, "5": 1, "6": 2 }, "France": { "4": 3, "5": 1, "6": 2 } } }
请注意，这不会改变 g_jsonData ，它只返回新对象。
要使用新对象，您必须将其分配给变量，当然：
var output = g_jsonData.reduce(func....);
您可以使代码更短（/更容易查看），如下所示：
g_jsonData.reduce(function(out, curr){ var c = curr.Country, s = curr.Subperiod, v = +curr.col1; //value cast to int already out.countries[c] = out.countries[c] || {}; out.countries[c][s] = (out.countries[c][s] || 0 ) + v; out.count[c] = out.count[c] || {}; out.count[c][s] = (out.count[c][s] || 0 ) + 1; out.columns[s] = (out.columns[s] || 0 ) + v; return out; }, {'columns':{},'countries':{},'count':{}});
现在，将col1变为变量名称相对容易。
更换：
v = +curr.col1;
附：
v = +curr['col1'];
要么：
v = +curr[someVariable];