课程链接
Curran的课程，通过 D3.js 的 scaleLinear, max, scaleBand, axisLeft, axisBottom，根据 .csv 文件生成一个横向柱状图。
【注】如果想造csv数据，可以使用通义千问，关于LinearScale与BandScale不懂的地方也可以在通义千问里提问
https://tongyi.aliyun.com/qianwen/
Linear Scale (线性比例尺)
定义： 线性比例尺是一种将输入域（通常是数值范围）线性地映射到输出范围的比例尺。它非常适合处理连续的数值数据。（大体就是处理数据）
Band Scale (带状比例尺)
定义： 带状比例尺是一种将输入域（通常是离散的类别值）映射到输出范围的比例尺。它主要用于处理分类数据，常用于条形图的 x 轴或 y 轴。（大体就是处理文字、名称）
【data.csv】
country,population
China,1415046
India,1354052
United States,326767
Indonaesia,266795
Brazil,210868
Pakistan,200814
Nigeria,195875
Bangladesh,166368
Russia,143965
Mexico,130759
【pokemon.csv】
Rank,Pokemon,Type,Base_Attack
1,Kommo-o,Dragon/Fighting,165
2,Kyurem-Black,Dragon/Ice,170
3,Groudon,Ground,180
4,Kyogre,Water,150
5,Deoxys-Attack Forme,Psychic,180
6,Mega Rayquaza,Dragon/Flying,180
7,Xerneas,Fairy,130
8,Yveltal,Dark/Flying,130
9,Mewtwo-Mega X,Psychic/Fighting,190
10,Zekrom,Dragon/Electric,170【style.css】
body {margin: 0;overflow: hidden;
}rect {fill: steelblue
}text {font-size: 1.4em;
}
【index.html】
<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><title>Document</title><link rel="stylesheet" href="./style.css"><script src="https://lf6-cdn-tos.bytecdntp.com/cdn/expire-1-M/d3/5.6.0/d3.min.js"type="application/javascript"></script>
</head><body><svg width="960" height="500"></svg><script>const select = d3.selectconst csv = d3.csvconst scaleLinear = d3.scaleLinearconst max = d3.maxconst scaleBand = d3.scaleBandconst axisLeft = d3.axisLeftconst axisBottom = d3.axisBottomconst svg = select('svg')const width = +svg.attr('width')const height = +svg.attr('height')const render = data => {// const xValue = d => d.population;// const yValue = d => d.country;const xValue = d => d.Base_Attack;const yValue = d => d.Pokemon;const margin = {top: 20,right: 40,bottom: 20,left: 160}const innerWidth = width - margin.left - margin.rightconst innerHeight = height - margin.top - margin.bottomconst xScale = scaleLinear().domain([0, max(data, xValue)]).range([0, innerWidth])const yScale = scaleBand().domain(data.map(yValue)).range([0, innerHeight]).padding(0.1)// const yAxis = axisLeft(yScale)const g = svg.append('g').attr('transform', `translate(${margin.left},${margin.top})`)// yAxis(g.append('g')) // 添加Y轴// 添加Y轴g.append('g').call(axisLeft(yScale)) // 添加X轴g.append('g').call(axisBottom(xScale)) .attr('transform',`translate(0,${innerHeight})`)g.selectAll('rect').data(data).enter().append('rect').attr('y', d => yScale(yValue(d))).attr('width', d => xScale(xValue(d))).attr('height', yScale.bandwidth())}csv('./data.csv').then(data => {data.forEach(d => {d.population = + d.population * 1000;});// console.log(data);render(data)})</script>
</body></html>
