[从头学数学] 第72节 平均数与条形统计图

剧情提要：
[机器小伟]在[工程师阿伟]的陪同下进入练气期第八层功法的修炼，
这次要修炼的目标是[平均数与条形统计图]。

正剧开始：

星历2016年02月04日 11:25:29, 银河系厄尔斯星球中华帝国江南行省。
[工程师阿伟]正在和[机器小伟]一起研究复式统计表。

小伟现在手头已经有了可以绘制单式条形图的工具，但是还需要复习一下用法。

<span style="font-size:18px;">function myDraw() { 
    var config = new PlotConfiguration();  
    config.init();  
    config.setPreference(); 
	
	//config.setSector(1,1,1,1);
	//config.axis2D(0, 0, 180);
	
	var stat = new Statistic();
	var data = [8,12,11,9,10];
	var text = ['18日', '19日', '20日', '21日', '22日'];
	
	stat.init(data, '日期', '销量/日');
	
	var x = 0, y = 20;
	stat.histogram(text, x, y);
}</span>

还可以竖着画：

然后大Boss登场了：

小伟决定先看看[人叫板老师]怎样处理的。

这样，复式条形图的初步方案就可以敲定了：

<span style="font-size:18px;">function myDraw() { 
    var config = new PlotConfiguration();  
    config.init();  
    config.setPreference(); 
	
	//config.setSector(1,1,1,1);
	//config.axis2D(0, 0, 180);
	
	var stat = new Statistic();
	var data = [[21,58],[27,54],[35,49],[46,43]];
	var text = ['1980', '1990', '2000', '2010'];
	var text2 = ['城镇', '农村'];
	
	stat.init(data, '年份', '人数/万人', 2);
	
	var x = 0, y = 20;
	stat.multiHistogram(text,text2, x, y);
	/*
	document.write(stat.max()+',');
	document.write(stat.min()+',');
	document.write(stat.mean()+',');*/
}

		//复式直方图
	this.multiHistogram = function(lableArray, lableArray2, xOffset, yOffset) {
		//lableArray是统计数据中横轴的描述
		//lableArray2是所统计的项目的描述
		lableArray = lableArray ? lableArray : [];
		var lables = lableArray.length;
		xOffset = xOffset ? xOffset : 0;
		yOffset = yOffset ? yOffset : 0;
		
		var colorArray = ['red', 'orange', '#0088FF', 'green', 'cyan', 'blue', '#FF00FF',
			'#888888', 'black'];
		var colors = colorArray.length;
			
		var height = 380, width = 580;
		
		plot.save()
			.translate(xOffset+60, yOffset+50);

		plot.setLineWidth(2)
			.setTextAlign('right');
			
		var max = Math.ceil(this.max());  
		var min = Math.floor(this.min()); 
		
		var mod = 1;
		while (max > mod * 10) {
			mod *= 10;
		}
		
		if (mod > 10) 
			mod /= 10;
		//最大值的末位为0的近似数，比如最大值25，最合适的近似数为30
		var adjmax = Math.ceil(max/mod)*mod;
		if (adjmax == max) {
			adjmax+=mod;
		}
		
		adjmax /= mod;
		
		var size = this.size();  
		var perH = Math.round((height-100) / adjmax); 
		var part = size*(this.multi+1)+1;
		var perW = Math.round((width-100) / part);
		
		//宽和高度边界
		var wBound = part*perW, hBound = adjmax*perH;
		plot.setLineWidth(5)
			.strokeRect(0, 0, wBound, hBound);
			
		this.axis2D(0, hBound, wBound+20, hBound+20, this.xLabel, this.yLabel);
			
		plot.setLineWidth(2);
		var count = 0;
		for (var i = hBound; i >-1; i -= hBound / 10) {
			plot.fillText((adjmax*mod/10*count).toFixed(0), -10, i+10, 30);
			count++;
			
			if (i > 0) {
				plot.beginPath()
					.moveTo(0, i)
					.lineTo(wBound, i)
					.closePath()
					.stroke();
			}
		}
		
		for (var i = 0; i < part; i++) {
			plot.beginPath()
				.moveTo(i*perW, 0)
				.lineTo(i*perW, hBound)
				.closePath()
				.stroke();
		}
		

		
		var xpos, xpos2;
		
		for (var i = 0; i < size; i++) { 
			for (var j = 0; j < this.multi; j++) {
				xpos = perW*((this.multi+1)*i+j+1);

				plot.setFillStyle(colorArray[j%colors]);  
				plot.fillRect(xpos, hBound, perW, -this.statisticalSample[i][j]/mod*perH); 
			

			}
			
			xpos2 = perW*((this.multi+1)*i+1) + 0.5*this.multi*perW;
			plot.setTextAlign('center');
			if (i < lables) {
				plot.fillText(lableArray[i], xpos2, 
					hBound+30, 100);  

			}
			//plot.fillText(this.statisticalSample[i].toFixed(0), xpos2, hBound+40, 100);  
		}  

		for (var j = 0; j < this.multi; j++) {
			plot.setFillStyle(colorArray[j%colors]);  
			plot.fillRect(wBound - 50, -20-25*(this.multi-j-1), 20, 12);
			plot.fillText(lableArray2[j], wBound-10, -20-25*(this.multi-j-1)+12, 50);
			
			
		}
		
		plot.restore();
	
	}</span>

<span style="font-size:18px;">function myDraw() { 
    var config = new PlotConfiguration();  
    config.init();  
    config.setPreference(); 
	
	//config.setSector(1,1,1,1);
	//config.axis2D(0, 0, 180);
	
	var stat = new Statistic();
	var data = [[17,13],[18,4],[8,8],[14,13],[7,16]];
	var text = ['乒乓球', '足球', '跑步', '游泳', '跳绳'];
	var text2 = ['男生', '女生'];
	
	stat.init(data, '项目', '人数', 2);
	
	var x = 0, y = 20;
	stat.multiHistogram(text,text2, x, y);
	/*
	document.write(stat.max()+',');
	document.write(stat.min()+',');
	document.write(stat.mean()+',');*/
}</span>

<span style="font-size:18px;">function myDraw() { 
    var config = new PlotConfiguration();  
    config.init();  
    config.setPreference(); 
	
	//config.setSector(1,1,1,1);
	//config.axis2D(0, 0, 180);
	
	var stat = new Statistic();
	var data = [[71,76],[74,78],[75,80],[77,82]];
	var text = ['1980','1990','2000', '2010'];
	var text2 = ['男', '女'];
	
	stat.init(data, '年份', '平均年龄/岁', 2);
	
	var x = 0, y = 20;
	stat.multiHistogram(text,text2, x, y);
	/*
	document.write(stat.max()+',');
	document.write(stat.min()+',');
	document.write(stat.mean()+',');*/
}</span>

<span style="font-size:18px;">function myDraw() { 
    var config = new PlotConfiguration();  
    config.init();  
    config.setPreference(); 
	
	//config.setSector(1,1,1,1);
	//config.axis2D(0, 0, 180);
	
	var stat = new Statistic();
	var data = [[36779,46106],[36564,54731],[34036,64125],[31373,74721],[29434,85900],[28512,98625]];
	var text = ['2006','2007','2008', '2009', '2010', '2011'];
	var text2 = ['固定电话', '移动电话'];
	
	stat.init(data, '年份', '用户/万户', 2);
	
	var x = 0, y = 20;
	stat.multiHistogram(text,text2, x, y);
	/*
	document.write(stat.max()+',');
	document.write(stat.min()+',');
	document.write(stat.mean()+',');*/
}</span>

到现在为止，小伟的统计类已经变成了：

<span style="font-size:18px;">/**
* @usage   统计类
* @author  mw
* @date    2016年01月05日  星期二  10:14:34 
* @param
* @return
*
*/
function Statistic() {
	this.statisticalSample = new Array();
	this.sampleSize = 0;
	this.multi = 1;
	this.xLabel = '';
	this.yLabel = '';

	//初始化
	this.init = function(array, textX, textY, multi) {
		//multi为复式统计中每个数据的项数
		this.statisticalSample = array;
		this.sampleSize = this.statisticalSample.length;
		this.multi = multi ? Math.round(multi) : 1;
		this.xLabel = textX;
		this.yLabel = textY;
	}
	
	this.axis2D = function(x, y, rx, ry, textX, textY) {
		//原点是(x, y), rx, ry分别是x轴的长度，y轴的长度
		//textX, textY分别为x轴和y轴的标注
		plot.save();
		
		plot.setFillStyle('black')
			.setStrokeStyle('black');
			
		plot.beginPath()
			.moveTo(x,y)
			.lineTo(x+rx,y)
			.closePath()
			.stroke();
			
		plot.beginPath()
			.moveTo(x,y-ry)
			.lineTo(x,y)
			.closePath()
			.stroke();		

		
		var r0 = 10;
		
		//x轴箭头
		plot.beginPath()
			.moveTo(x+rx- r0*Math.cos(Math.PI/3), y-r0*Math.sin(Math.PI/3))
			.lineTo(x+rx+r0*Math.sin(Math.PI/3), y)
			.lineTo(x+rx -r0*Math.cos(Math.PI/3), y+r0*Math.sin(Math.PI/3))
			.closePath()
			.fill()
		
		plot.setTextAlign('left')
			.fillText(textX, x+rx, y+25, 40);
		plot.setTextAlign('right')
			.fillText(textY, x-10, y-ry+10, 40);
		
		//y轴箭头
		plot.beginPath()
			.moveTo(x+ r0*Math.sin(Math.PI/3), y-ry+r0*Math.cos(Math.PI/3))
			.lineTo(x, y-ry-r0*Math.sin(Math.PI/3))
			.lineTo(x-r0*Math.sin(Math.PI/3), y-ry+r0*Math.cos(Math.PI/3))
			.closePath()
			.fill()
		
		plot.restore();
	}	
	
	//最大值
	this.max = function() {
		var max = Number.NEGATIVE_INFINITY;
		if (this.multi == 1) {
			for (var i = 0; i < this.sampleSize; i++) {
		
				if (max < this.statisticalSample[i]) {
					max = this.statisticalSample[i];
				}
			}
		}
		else {
			for (var i = 0; i < this.sampleSize; i++) {
				for (var j = 0; j < this.multi; j++) {
		
					if (max < this.statisticalSample[i][j]) {
						max = this.statisticalSample[i][j];
					}
				}
			}
			
		}
		return max;
	}
	
	//最小值
	this.min = function() {
		var min = Number.POSITIVE_INFINITY;
		if (this.multi == 1) {
			for (var i = 0; i < this.sampleSize; i++) {
		
				if (min > this.statisticalSample[i]) {
					min = this.statisticalSample[i];
				}
			}
		}
		else {
			for (var i = 0; i < this.sampleSize; i++) {
				for (var j = 0; j < this.multi; j++) {
		
					if (min > this.statisticalSample[i][j]) {
						min = this.statisticalSample[i][j];
					}
				}
			}			
		}
		return min;
	}
	
	//总计
	this.total = function() {
		if (this.multi == 1) {
			var value  = 0;
			for (var i = 0; i < this.sampleSize; i++) {
				value += this.statisticalSample[i];
			}
			return value;
		}
		else {
			var value = [];
			var tmp = 0;
			for (var j = 0; j < this.multi; j++) {
				tmp = 0;
				for (var i = 0; i < this.sampleSize; i++) {
					tmp += this.statisticalSample[i][j];
				}
				value.push(tmp);
				
			}
			return value;
			
		}
	}
		
	
	//平均数
	this.mean = function() {
		
		var value = this.total();
		if (this.sampleSize != 0) {
			for (var i = 0; i < value.length; i++) {
				value[i] /= this.sampleSize;
			}
		}
			
		return value;
	}
		
	
	//样本数量
	this.size = function() {
		return this.sampleSize;
	}
	
	//直方图
	this.histogram = function(lableArray, xOffset, yOffset) {
		lableArray = lableArray ? lableArray : [];
		var lables = lableArray.length;
		xOffset = xOffset ? xOffset : 0;
		yOffset = yOffset ? yOffset : 0;
		
		var colorArray = ['red', 'orange', '#0088FF', 'green', 'cyan', 'blue', '#FF00FF',
			'#888888', 'black'];
		var colors = colorArray.length;
			
		var height = 380, width = 580;
		
		plot.save()
			.translate(xOffset+60, yOffset+50);

		plot.setLineWidth(2)
			.setTextAlign('right');
			
		var max = Math.ceil(this.max());  
		var min = Math.floor(this.min()); 
		
		var mod = 1;
		while (max > mod * 10) {
			mod *= 10;
		}
		
		if (mod > 10) 
			mod /= 10;
		//最大值的末位为0的近似数，比如最大值25，最合适的近似数为30
		var adjmax = Math.ceil(max/mod)*mod;
		if (adjmax == max) {
			adjmax+=mod;
		}
		
		adjmax /= mod;
		
		var size = this.size();  
		var perH = Math.round((height-100) / adjmax);  
		var perW = Math.round((width-100) / (size*2+1));
		
		//宽和高度边界
		var wBound = (2*size+1)*perW, hBound = adjmax*perH;
		plot.setLineWidth(5)
			.strokeRect(0, 0, wBound, hBound);
			
		this.axis2D(0, hBound, wBound+20, hBound+20, this.xLabel, this.yLabel);
			
		plot.setLineWidth(2);
		var count = 0;
		for (var i = hBound; i >-1; i -= hBound / 10) {
			plot.fillText((adjmax*mod/10*count).toFixed(0), -10, i+10, 30);
			count++;
			
			if (i > 0) {
				plot.beginPath()
					.moveTo(0, i)
					.lineTo(wBound, i)
					.closePath()
					.stroke();
			}
		}
		
		for (var i = 0; i < 2*size+1; i++) {
			plot.beginPath()
				.moveTo(i*perW, 0)
				.lineTo(i*perW, hBound)
				.closePath()
				.stroke();
		}
		

		
		var xpos, xpos2;
		
		for (var i = 0; i < size; i++) { 
			xpos = perW*(1+2*i);
			xpos2 = xpos + 0.5*perW;
			plot.setFillStyle(colorArray[i%colors]);  
			plot.fillRect(perW*(1+2*i), hBound, perW, -this.statisticalSample[i]/mod*perH); 
			
			plot.setTextAlign('center');
			if (i < lables) {
				plot.fillText(lableArray[i], xpos2, 
					hBound+30, 100);  

			}
			//plot.fillText(this.statisticalSample[i].toFixed(0), xpos2, hBound+40, 100);  
		}  

		
		plot.restore();
	
	}
		
	//垂直方向直方图
	this.verticalhistogram = function(lableArray, xOffset, yOffset) {
		lableArray = lableArray ? lableArray : [];
		var lables = lableArray.length;
		xOffset = xOffset ? xOffset : 0;
		yOffset = yOffset ? yOffset : 0;
		
		var colorArray = ['red', 'orange', '#0088FF', 'green', 'cyan', 'blue', '#FF00FF',
			'#888888', 'black'];
		var colors = colorArray.length;
			
		var height = 380, width = 580;
		
		plot.save()
			.translate(xOffset+60, yOffset+50);
			
		var max = Math.ceil(this.max());  
		var min = Math.floor(this.min()); 
		
		var mod = 1;
		while (max > mod * 10) {
			mod *= 10;
		}
		

		//最大值的末位为0的近似数，比如最大值25，最合适的近似数为30
		if (mod > 10) 
			mod /= 10;
		var adjmax = Math.ceil(max/mod)*mod;
		if (adjmax == max) {
			adjmax+=mod;
		}
		
		adjmax /= mod;
		
		
		var size = this.size();  
		var perH = Math.round((height-100) / (size*2+1));			  
		var perW = Math.round((width-100) / adjmax);
		
		//宽和高度边界
		var hBound = (2*size+1)*perH, wBound = adjmax*perW;
		plot.setLineWidth(5)
			.strokeRect(0, 0, wBound, hBound);
			
		this.axis2D(0, hBound, wBound+20, hBound+20, this.xLabel, this.yLabel);
			
		plot.setLineWidth(2)
			.setTextAlign('center');
		var count = 0;
		for (var i = 0; i < wBound+1; i += wBound / 10) {
			plot.fillText((adjmax*mod/10*count).toFixed(0), i, hBound+25, 30);
			count++;
			
			if (i > 0) {
				plot.beginPath()
					.moveTo(i, 0)
					.lineTo(i, hBound)
					.closePath()
					.stroke();
			}
		}
		
		for (var i = 0; i < 2*size+1; i++) {
			plot.beginPath()
				.moveTo(0, i*perH)
				.lineTo(wBound, i*perH)
				.closePath()
				.stroke();
		}
		

		
		var ypos, ypos2;
		
		for (var i = 0; i < size; i++) { 
			ypos = perH*(1+2*i);
			ypos2 = ypos + 0.5*perH+5;
			plot.setFillStyle(colorArray[i%colors]);  
			plot.fillRect(0, ypos, this.statisticalSample[i]/mod*perW, perH); 
			
			plot.setTextAlign('right');
			if (i < lables) {
				plot.fillText(lableArray[i], -10, ypos2, 100);  

			}
			
		}  

		
		plot.restore();
	
	}
	
		//复式直方图
	this.multiHistogram = function(lableArray, lableArray2, xOffset, yOffset) {
		//lableArray是统计数据中横轴的描述
		//lableArray2是所统计的项目的描述
		lableArray = lableArray ? lableArray : [];
		var lables = lableArray.length;
		xOffset = xOffset ? xOffset : 0;
		yOffset = yOffset ? yOffset : 0;
		
		var colorArray = ['red', 'orange', '#0088FF', 'green', 'cyan', 'blue', '#FF00FF',
			'#888888', 'black'];
		var colors = colorArray.length;
			
		var height = 380, width = 580;
		
		plot.save()
			.translate(xOffset+60, yOffset+50);

		plot.setLineWidth(2)
			.setTextAlign('right');
			
		var max = Math.ceil(this.max());  
		var min = Math.floor(this.min()); 
		
		var mod = 1;
		while (max > mod * 10) {
			mod *= 10;
		}
		
		if (mod > 10) 
			mod /= 10;
		//最大值的末位为0的近似数，比如最大值25，最合适的近似数为30
		var adjmax = Math.ceil(max/mod)*mod;
		if (adjmax == max) {
			adjmax+=mod;
		}
		
		adjmax /= mod;
		
		var size = this.size();  
		var perH = Math.round((height-100) / adjmax); 
		var part = size*(this.multi+1)+1;
		var perW = Math.round((width-100) / part);
		
		//宽和高度边界
		var wBound = part*perW, hBound = adjmax*perH;
		plot.setLineWidth(5)
			.strokeRect(0, 0, wBound, hBound);
			
		this.axis2D(0, hBound, wBound+20, hBound+20, this.xLabel, this.yLabel);
			
		plot.setLineWidth(2);
		var count = 0;
		for (var i = hBound; i >-1; i -= hBound / 10) {
			plot.fillText((adjmax*mod/10*count).toFixed(0), -10, i+10, 30);
			count++;
			
			if (i > 0) {
				plot.beginPath()
					.moveTo(0, i)
					.lineTo(wBound, i)
					.closePath()
					.stroke();
			}
		}
		
		for (var i = 0; i < part; i++) {
			plot.beginPath()
				.moveTo(i*perW, 0)
				.lineTo(i*perW, hBound)
				.closePath()
				.stroke();
		}
		

		
		var xpos, xpos2;
		
		for (var i = 0; i < size; i++) { 
			for (var j = 0; j < this.multi; j++) {
				xpos = perW*((this.multi+1)*i+j+1);

				plot.setFillStyle(colorArray[j%colors]);  
				plot.fillRect(xpos, hBound, perW, -this.statisticalSample[i][j]/mod*perH); 
			

			}
			
			xpos2 = perW*((this.multi+1)*i+1) + 0.5*this.multi*perW;
			plot.setFillStyle('black');
			plot.setTextAlign('center');
			if (i < lables) {
				plot.fillText(lableArray[i], xpos2, 
					hBound+30, 100);  

			}
			//plot.fillText(this.statisticalSample[i].toFixed(0), xpos2, hBound+40, 100);  
		}  

		plot.setTextAlign('left');
		for (var j = 0; j < this.multi; j++) {			
			plot.setFillStyle(colorArray[j%colors]);  
			plot.fillRect(wBound - 50, -20-25*(this.multi-j-1), 20, 12);
			plot.fillText(lableArray2[j], wBound-20, -20-25*(this.multi-j-1)+12, 50);
			
			
		}
		
		plot.restore();
	
	}
}</span>

本节到此结束，欲知后事如何，请看下回分解。