How to easily draw beautiful statistical charts using ECharts and golang

How to use ECharts and golang to easily draw beautiful statistical charts

With the continuous accumulation and application of data, statistical charts have become an important way to display data. . In this field, ECharts is a popular open source JavaScript chart library. It is powerful, easy to use and supports a large number of styles and chart types, so it has been widely used in development. At the same time, as an efficient programming language, golang is becoming increasingly popular in Web back-end development.

This article mainly introduces how to use ECharts and golang to draw beautiful statistical charts, and gives specific code examples.

1. Preparation work

Before developing statistical charts, we need to prepare the following tools and environments:

• Golang environment
• Beego Framework
• ECharts Library

Among them, the Golang environment can be downloaded and installed through the official website, and the Beego framework can be installed through the following command:

go get github.com/astaxie/beego

ECharts The library can be installed with the following command:

npm install echarts --save

2. Drawing histogram

First, we try to draw a simple histogram. The code is as follows:

package controllers

import (
    "github.com/astaxie/beego"
)

type MainController struct {
    beego.Controller
}

func (this *MainController) Get() {
    this.Data["Website"] = "beego.me"
    this.Data["Email"] = "astaxie@gmail.com"
    this.TplName = "index.tpl"

    data := []int{10, 52, 200, 334, 390, 330, 220}
    this.Data["chart_data"] = data
    this.Data["chart_type"] = "bar"
}

In the code, we define a controller named MainController and implement the Get method. Among them, we define an array named data, which contains the data of the histogram. We then pass this data to the "chart_data" variable in the template, as well as the chart type "chart_type" variable. Specifically, we used "bar" as the type of histogram.

Next, we need to layout in the template and use the ECharts library to render the chart. The code is as follows:

{{.chart_data}}
{{.chart_type}}

{{if .chart_data}}
    <div id="myChart" style="width: 600px;height:400px;"></div>
{{end}}
<script src="https://cdn.bootcdn.net/ajax/libs/echarts/3.5.4/echarts.min.js"></script>
<script>
$(document).ready(function(){
    var myChart = echarts.init(document.getElementById('myChart'));
    var option = {
        title: {
            text: '柱状图'
        },
        tooltip: {},
        legend: {
            data:['销量']
        },
        xAxis: {
            data: ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
        },
        yAxis: {},
        series: [{
            name: '销量',
            type: '{{.chart_type}}',
            data: {{.chart_data}},
            label: {
                normal: {
                    show: true,
                    position: 'top'
                }
            }
        }]
    };
    myChart.setOption(option);
});
</script>

In the code, we first use {{.chart_data}} and {{.chart_type}} to output the data and chart type so that we can check the correctness of the data when debugging. Then, we use conditional statements to determine whether the data has been passed, and the chart area will be displayed only after the data is passed.

Next, we introduced the ECharts library and used the echarts.init method to initialize a DOM element with a specified ID. In this example, we added some basic configuration items, such as title, tooltip, legend, xAxis, yAxis, series, etc. Among them, xAxis and yAxis define the data of the horizontal axis and the vertical axis respectively, and series is used to define the data of the chart.

3. Drawing pie charts

In addition to histograms, we can also use ECharts and golang to draw other types of charts. Next we try to draw a pie chart. The code is as follows:

package controllers

import (
    "github.com/astaxie/beego"
)

type MainController struct {
    beego.Controller
}

func (this *MainController) Get() {
    this.Data["Website"] = "beego.me"
    this.Data["Email"] = "astaxie@gmail.com"
    this.TplName = "index.tpl"

    data := map[string]int{"直接访问":335, "邮件营销":310, "联盟广告":234, "视频广告":135, "搜索引擎":1548}
    this.Data["chart_data"] = data
    this.Data["chart_type"] = "pie"
}

In the code, we define a map named data, which contains the data of the pie chart. Similar to the previous section, we pass this data to the "chart_data" variable in the template, as well as the chart type "chart_type" variable. However, this time we are using "pie" as the pie chart type.

Next, we lay out the template and use the ECharts library to render the chart. The code is as follows:

{{.chart_data}}
{{.chart_type}}

{{if .chart_data}}
    <div id="myChart" style="width: 600px;height:400px;"></div>
{{end}}
<script src="https://cdn.bootcdn.net/ajax/libs/echarts/3.5.4/echarts.min.js"></script>
<script>
$(document).ready(function(){
    var myChart = echarts.init(document.getElementById('myChart'));
    var option = {
        title: {
            text: '饼图'
        },
        tooltip: {
            trigger: 'item',
            formatter: '{a} <br/>{b}: {c} ({d}%)'
        },
        legend: {
            orient: 'vertical',
            left: 10,
            data: ['直接访问','邮件营销','联盟广告','视频广告','搜索引擎']
        },
        series: [
            {
                name: '访问来源',
                type: '{{.chart_type}}',
                radius: '45%',
                center: ['50%', '60%'],
                data: [
                    {value: 335, name: '直接访问'},
                    {value: 310, name: '邮件营销'},
                    {value: 234, name: '联盟广告'},
                    {value: 135, name: '视频广告'},
                    {value: 1548, name: '搜索引擎'}
                ],
                label: {
                    normal: {
                        show: false,
                        position: 'inside'
                    },
                    emphasis: {
                        show: true,
                        textStyle: {
                            fontSize: '20',
                            fontWeight: 'bold'
                        }
                    }
                },
                labelLine: {
                    normal: {
                        show: false
                    }
                }
            }
        ]
    };
    myChart.setOption(option);
});
</script>

In the code, we first use {{.chart_data}} and {{.chart_type}} to output data and chart types. Then, we also use conditional statements to control whether the chart area is displayed.

In the configuration items of the chart, we use the "data" array with a specific format to define the data of the chart. Among them, value is used to represent the size of the data, and name is used to represent the name of the data. At the same time, we can also use attributes such as "label" and "labelLine" to set labels.

4. Summary

This article introduces how to use ECharts and golang to easily draw beautiful statistical charts. We first implemented a simple bar chart and pie chart, and gave specific code examples. Through these examples, we can learn how to use ECharts and combine it with the golang framework to achieve data visualization needs.

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