[从头学数学] 第101节 比例

剧情提要：
[机器小伟]在[工程师阿伟]的陪同下进入练气期第十二层功法的修炼，
这次要修炼的目标是[比例]。

正剧开始：

星历2016年02月21日 14:45:36, 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]一起研究比例的相关问题。

<span style="font-size:18px;">>>> scale([2.4,1.6,60,'q']);
2.4  :  1.6  =  60  :  40.0

#求比例
def scale(array):
    if (len(array)==4):
        # <0> : <1> = <2> : <3>
        if (array[0] == 'q'):
            array[0] = array[2]/array[3]*array[1];
        elif (array[1] == 'q'):
            array[1] = array[3]/array[2]*array[0];
        elif (array[2] == 'q'):
            array[2] = array[0]/array[1]*array[3];
        elif (array[3] == 'q'):
            array[3] = array[1]/array[0]*array[2];
        else:
            pass;
        
        print(round(array[0],3), ' : ', round(array[1], 3), ' = ',\
              round(array[2],3), ' : ', round(array[3],3));
    else:
        print('[<0> : <1> = <2> : <3>]');

    return;   </span>

<span style="font-size:18px;">>>> scale(['q', 320,1,10]);
32.0  :  320  =  1  :  10</span>

<span style="font-size:18px;">>>> scale([24.3, 'q', 1, 20]);
24.3  :  486.0  =  1  :  20
>>> scale([1, 20, 'q', 11.76]);
1  :  20  =  0.588  :  11.76
>>> scale([1, 10, 19.6, 'q']);
1  :  10  =  19.6  :  196.0
>>> scale([500, 1, 35000, 'q']);
500  :  1  =  35000  :  70.0
>>> scale([3,8,15,40]);
3  :  8  =  15  :  40
>>> scale([2.5,0.5,2,0.4]);
2.5  :  0.5  =  2  :  0.4
>>> </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 x, y;
	
	for (var i = 0; i < 8; i++) {
		x = i * 20;
		y = -x * 0.5;
		
		shape.fillCircle(x, y, 5);
	}
    
}</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 x, y;
	
	plot.scale(2, 2);
	for (var i = 0; i < 8; i++) {
		x = i*10;
		y = -300/ x;
		
		shape.fillCircle(x, y, 2);
	}
    
}
	</span>

<span style="font-size:18px;">>>> scale([7.8, 'q', 1, 4*10**5]);
7.8  :  3120000.0  =  1  :  400000
>>> 3120000/10**6
3.12
>>> </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 x, y;
	
	var a = [[0,0], [-200, 0],[200,0],[0,250]];
	
	for (var i = 0; i < a.length; i++) {
		for (var j = 0; j < 2; j++) {
			if (j == 0) {
				a[i][j] *= 0.01*37.8;
			}
			else {
				a[i][j] *= -0.01*37.8;
			}
		}
	}
	
	shape.pointDraw(a, 'red');
	
	var ruler = new Ruler();
	ruler.ruler(15, 0, 0, 0);
    
}</span>

<span style="font-size:18px;">/**
* @usage   绘制点阵列
* @author  mw
* @date    2016年02月21日  星期日  15:16:47 
* @param
* @return
*
*/
	this.pointDraw = function(array, style) {
		style = style ? style : 'black';
		
		plot.save()
			.setFillStyle(style);
		
		var a = new Array();
		a = array[0];
		if (a.length != 2) {
			while (array.length > 0) {  
				shape.fillCircle(array.shift(), array.shift(), 5);  
			}   
		}
		else {				
			while (array.length > 0) {  
				a = array.shift();
				shape.fillCircle(a[0], a[1], 5);  
			}  	
		}
		
		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 x = 1*37.8, y = 1.75*37.8, w = 2*37.8, h = 3.5 * 37.8;

	plot.setStrokeStyle('red');
	
	for (var i = 0; i < 3; i++) {
		shape.strokeRect(x, y, w, h);
		
		x += w;
	}
	
	var h2 = 0.75*37.8;
	plot.strokeRect(0, -h2, w*3, h2);
	
	x = 1*37.8, y -= (h2+h);
	
	for (var i = 0; i < 2; i++) {
		shape.strokeRect(x, y, w, h);
		
		x += w;
	}
    
}</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 x, y;
	
	var a = [[0,0], [-500, 0],[-500,300],[500,300], [500, -100]];
	var b = [];
	
	
	for (var i = 0; i < a.length; i++) {
		for (var j = 0; j < 2; j++) {
			if (j == 0) {
				a[i][j] *= 0.01*37.8;
			}
			else {
				a[i][j] *= -0.01*37.8;
			}
			
			b.push(a[i][j]);
		}
	}
	
	var color = ['blue', 'orange', 'pink', 'green', 'purple'];
	
	for (var i = 0; i < b.length; i+=2) {
		plot.setFillStyle(color[i/2%5]);
		shape.fillRect(b[i], b[i+1], 50, 50);
		
	}
	
	shape.pointDraw(a, 'red');
	//var ruler = new Ruler();
	//ruler.ruler(15, 0, 0, 0);
    
}</span>

<span style="font-size:18px;">>>> scale([1.5,2.4,'q', 4]);
1.5  :  2.4  =  2.5  :  4
>>> scale([6, 10.6, 14, 'q']);
6  :  10.6  =  14  :  24.733</span>

本节到此结束，欲知后事如何，请看下回分解。