javascript - 使用mysql数据创建条形图

我想使用以JSON格式返回的mysql数据创建栏。

[
  {
    "Score": "84",
    "Trainer": "Jamshaid",
    "Subject Name": "Java"
  },
  {
    "Score": "50",
    "Trainer": "Zaid",
    "Subject Name": "Android"
  },
  {
    "Score": "40",
    "Trainer": "Sajjad",
    "Subject Name": "iOS"
  },
  {
    "Score": "50",
    "Trainer": "Jamshaid",
    "Subject Name": "iOS"
  }
]

我想创建类似this的图表

但是问题是，这是从Table格式化的。但是我有JSON中的数据，如上所示。

这是我关注的链接。我们可以将JSON数据转换为一种格式，以便它可以根据所示数据填充图表吗？

https://blueflame-software.com/bar-chart-with-data-from-mysql-using-highcharts/

最佳答案

您可以在Javascript中处理JSON来构建图表所需的数据，如下所示：

var jsonFromServer = [
  {
    "Score": "84",
    "Trainer": "Jamshaid",
    "Subject Name": "Java"
  },
  {
    "Score": "50",
    "Trainer": "Zaid",
    "Subject Name": "Android"
  },
  {
    "Score": "40",
    "Trainer": "Sajjad",
    "Subject Name": "iOS"
  },
  {
    "Score": "50",
    "Trainer": "Jamshaid",
    "Subject Name": "iOS"
  }
];

上面是从服务器捕获的数据中的一个变量

以下代码可帮助您从JSON响应中提取Y轴值（即唯一的主题名称）：

function getSubjects(){
    var subjectsMap = {};
  $.each(jsonFromServer, function(index, value){
    if(!subjectsMap[value['Subject Name']]){
        subjectsMap[value['Subject Name']] = 1;
    }
  });
  return $.map(subjectsMap, function(index, val){ return val; });
}

然后，我们需要提取不同学科中每个培训师的分数，其形式应为：[{name：“ Trainer”，data：[]}]其中，data是学科中分数数组，其顺序应与顺序相同Y轴数据中出现的对象的数量。可以使用以下代码实现：

function getTrainers(){
    var trainersMap = {};
  $.each(jsonFromServer, function(index, value){
    if(!trainersMap[value['Trainer']]){
        trainersMap[value['Trainer']] = 1;
    }
  });
  return $.map(trainersMap, function(index, val){ return val; });
}
function getMarks(){
  var subjects = getSubjects();
  var trainers= getTrainers();
  var marks = {};
  //initialize the trainers scores in all subjects to 0
   $.each(trainers, function(index, trainer){
    if ( !marks[trainer]){
        marks[trainer] = {};
    }
    $.each(subjects, function(idx2, sub){
        marks[trainer][sub] = 0;
    });
  });

  //now populate with the actual values obtained from server
  $.each(subjects, function(idx2, sub){
    $.each(jsonFromServer, function(index, value){
        var trainer = value['Trainer'];
        var subName = value['Subject Name'];
      var score = value['Score'];
      if ( sub == subName){
            marks[trainer][sub] = score;
      }
    });

  });

  //now format the marks object into the format required for highcharts
  //i.e an array of object with properties [{name: "", data:[]}]
  return $.map(marks, function(val, index){
    var scoreArray = [];
    $.each(val, function(index, score){
        scoreArray.push(parseInt(score));
    });
    return {"name": index, "data": scoreArray};
  });

}

可以在提琴here中找到工作代码。