Crossfilter减少::查找唯一数 [英] Crossfilter reduce :: find number of uniques

问题描述

我正在尝试为数据集属性组创建一个自定义的reduce函数，该函数将求和另一个属性的许多唯一值。

I am trying to create a custom reduce function for a dataset attribute group that would sum a number of unique values for another attribute.

例如，我的数据集看起来就像团队成员对项目执行的操作的列表一样：

For example, my dataset looks like a list of actions on projects by team members:

{ project:"Website Hosting", teamMember:"Sam", action:"email" },
{ project:"Website Hosting", teamMember:"Sam", action:"phoneCall" },
{ project:"Budjet", teamMember:"Joe", action:"email" },
{ project:"Website Design", teamMember:"Joe", action:"design" },
{ project:"Budget", teamMember:"Sam", action:"email" }

因此，团队成员通过每行执行一项操作来处理可变数量的项目。我按团队成员确定维度，并希望通过项目（独特）的数量来减少维度。

So, team members work on a variable number of projects by performing one action per line. I have a dimension by team member, and would like to reduce it by the number of projects (uniques).

我尝试了以下操作（将项目存储在唯一数组中）而没有成功（对不起，这可能会伤害您的眼睛）：

I tried the below (storing project in a uniques array) without success (sorry, this might hurt your eyes):

var teamMemberDimension = dataset.dimension(function(d) {
    return d.teamMember;
});

        var teamMemberDimensionGroup = teamMemberDimension.group().reduce(
            // add
            function(p,v) {
                if( p.projects.indexOf(v.project) == -1 ) {
                    p.projects.push(v.project);
                    p.projectsCount += 1;
                }
                return p;
            },
            // remove
            function(p,v) {
                if( p.projects.indexOf(v.projects) != -1 ) {
                    p.projects.splice(p.projects.indexOf(v.projects), 1);
                    p.projectsCount -= 1;
                }
                return p;
            },
            // init
            function(p,v) {
                return { projects:[], projectsCount:0 }
            }
        );

非常感谢！

编辑后DJ Martin的答案::

Edit after DJ Martin's answer ::

因此，更清楚地说，我想得到的数字是：

So, to be clearer, I would like to get the numbers I am after here would be:

-----------
Sam : 2 (projects he is workin on, no matter the number of actions)
Joe : 2 (projects he is workin on, no matter the number of actions)
-----------

DJ Martin提供的答案将我带到了那里。但是，我希望找到一种在DC.JS条形图中使用这些数字的方法，而不是对表进行硬编码。当我只使用动作数（仅是reduceCount（））时，我的操作如下：

The answer provided by DJ Martin gets me there. But rather than hard coding a table, I would like to find a way to use these numbers for my DC.JS bar chart. When I was only using the number of actions (so just a reduceCount() ), I did it like below:

teamMemberChart.width(270)
    .height(220)
    .margins({top: 5, left: 10, right: 10, bottom: 20})
    .dimension(teamMemberDimension)
    .group(teamMemberDimensionGroup)
    .colors(d3.scale.category20())
    .elasticX(true)
    .xAxis().ticks(4);

我想group（）中可能会有一些更改。

I guess there might be something to change in the group().

推荐答案

更新后的答案

对不起，我误解了这个问题……您实际上是正确的。您只需要维护每个项目的计数，以便您的减法函数知道何时删除该值。

Sorry I misunderstood the question... you are actually on the right track. You'll just need to maintain a count of each project so that your subtract function can know when to remove the value.

teamMemberGroup = teamMemberDimension.group().reduce(

        function (p, d) {
            if( d.project in p.projects)
                p.projects[d.project]++;
            else p.projects[d.project] = 1;
            return p;
        },

        function (p, d) {
            p.projects[d.project]--;
            if(p.projects[d.project] === 0)
                delete p.projects[d.project];
            return p;
        },

        function () {
            return {projects: {}};
        });

以下是更新的小提琴： http://jsfiddle.net/djmartin_umich/3LyhL/

Here is an updated fiddle: http://jsfiddle.net/djmartin_umich/3LyhL/

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