当前位置 博文首页 > boysoft2002的专栏：Python 探究“一行代码画爱心”的秘密，去向
今天7月8号，恰逢儿子生日，我来画个爱心向他表达一下爱意吧：
>>> print('\n'.join([''.join([('ILoveYangCheng'[(x-y)%len('ILoveYangCheng')] if((x*0.05)**2+(y*0.1)**2-1)**3-(x*0.05)**2*(y*0.1)**3<=0 else' ') for x in range(-30,30)]) for y in range(13,-12,-1)]))
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>>> 网上流传了很多类似这种“一行代码画爱心”的文章，但大多数都没作深入研究，有的甚至是收费栏目中还有改错代码的，比如 %‘字串实际长度’ 都直接‘%8’。下面，我来对此代码作点解析，告诉小白们爱心到底是怎么画出来的？
探究一：去掉字符串，全部用'.'代替
>>> print('\n'.join([''.join([('.' if((x*0.05)**2+(y*0.1)**2-1)**3-(x*0.05)**2*(y*0.1)**3<=0 else' ') for x in range(-30,30)]) for y in range(13,-12,-1)]))
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>>> 探究二：其实就是心形线的函数式在起作用，换成直线看效果
>>> print('\n'.join([''.join([('.' if y==x+1 else' ') for x in range(-30,30)]) for y in range(15,-15,-1)]))
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>>> # 直线方程 y = x + 1直线方程 y = x+1 斜率1的倾角看上去不是45度，是因为x,y的长度比不是1:1。
方程式换成不等式 y > = x + 1 图像就成为一个区域，换个抛物线试试效果：
>>> print('\n'.join([''.join([('.' if y>=0.035*x**2-12 else' ') for x in range(-30,30)]) for y in range(15,-15,-1)]))
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>>> 抛物线内部区域： y >= 0.035 x2 - 12探究三：换个心形方程式
网上随便搜索了一张心形方程式的图片：
方程x,y的取值范围有点小，可以先放大10倍：?0.01*x*x+(0.1*y-pow(0.01*x*x,1/3))**2-1=0
由于纵横比不为1，再适当调整各个系数的大小；还有我们的坐标系是整数点，想和直线方程一样显示边界点不太现实，所以只能以?f(x,y)<=0的形式显示图形区域。若<=换成>=，则相当于图章的阳刻和阴刻的区别。
>>> print('\n'.join([''.join([('HannYang'[(x+y+78)%8] if 0.003*x*x+(0.075*y-pow(0.0015*x*x,1/3))**2-0.6<=0 else' ') for x in range(-30,30)]) for y in range(15,-12,-1)]))
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>>> #字符串的索引号表达式也可以修改：str[(表达式)&len(str)]print('\n'.join([''.join([('HannYang'[x%8-2] if 0.003*x*x+(0.075*y-pow(0.0015*x*x,1/3))**2-0.6>=0 else' ') for x in range(-30,30)]) for y in range(16,-12,-1)]))
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>>> 探究四：字符串换成中文汉字
需要把?else 后的填充空格换成2个半角空格或1个全角空格
>>> print('\n'.join([''.join([('我爱杨程'[(x-y)%4-3] if((x*0.08)**2+(y*0.1)**2-1)**3-(x*0.08)**2*(y*0.1)**3<=0 else ' ') for x in range(-20,20)]) for y in range(13,-12,-1)]))
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>>> 如此，掌握了原理，就去网上找各种方程式来创作你自己的图形吧！大胆去向心爱的人表白吧！！
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