lua学习笔记之五(Lua中的数学库) · Lua学习笔记

### Lua中的数学库 Lua5.1中数学库的所有函数如下表： math.pi 为圆周率常量 = 3.14159265358979323846 表1 <table border="1" cellspacing="0" cellpadding="0" width="574"><tbody><tr><td style="background:#99CCFF">数学库</td><td style="background:#99CCFF">说明</td><td style="background:#99CCFF">例子</td><td style="background:#99CCFF">方法</td></tr><tr><td>abs</td><td valign="bottom">取绝对值</td><td valign="bottom">math.abs(-15)</td><td valign="bottom">15</td></tr><tr><td>acos</td><td valign="bottom">反余弦函数</td><td valign="bottom">math.acos(0.5)</td><td valign="bottom">1.04719755</td></tr><tr><td>asin</td><td valign="bottom">反正弦函数</td><td valign="bottom">math.asin(0.5)</td><td valign="bottom">0.52359877</td></tr><tr><td>atan2</td><td valign="bottom">x / y的反正切值</td><td valign="bottom">math.atan2(90.0, 45.0)</td><td valign="bottom">1.10714871</td></tr><tr><td>atan</td><td valign="bottom">反正切函数</td><td valign="bottom">math.atan(0.5)</td><td valign="bottom">0.463647609</td></tr><tr><td>ceil</td><td valign="bottom">不小于x的最大整数</td><td valign="bottom">math.ceil(5.8)</td><td valign="bottom">6</td></tr><tr><td>cosh</td><td valign="bottom">双曲线余弦函数</td><td valign="bottom">math.cosh(0.5)</td><td valign="bottom">1.276259652</td></tr><tr><td>cos</td><td valign="bottom">余弦函数</td><td valign="bottom">math.cos(0.5)</td><td valign="bottom">0.87758256</td></tr><tr><td>deg</td><td valign="bottom">弧度转角度</td><td valign="bottom">math.deg(math.pi)</td><td valign="bottom">180</td></tr><tr><td>exp</td><td valign="bottom">计算以e为底x次方值</td><td valign="bottom">math.exp(2)</td><td valign="bottom">2.718281828</td></tr><tr><td>floor</td><td valign="bottom">不大于x的最大整数</td><td valign="bottom">math.floor(5.6)</td><td valign="bottom">5</td></tr><tr><td>fmod （mod）</td><td valign="bottom">取模运算</td><td valign="bottom">math.mod(14, 5)</td><td valign="bottom">4</td></tr><tr><td>frexp</td><td valign="bottom">把双精度数val分解为数字部分（尾数）和以2为底的指数n，即val=x*2n</td><td valign="bottom">math.frexp(10.0)</td><td valign="bottom">0.625 4</td></tr><tr><td>ldexp</td><td valign="bottom">计算value * 2的n次方</td><td valign="bottom">math.ldexp(10.0, 3)</td><td valign="bottom">80 = 10 * (2 ^3)</td></tr><tr><td>log10</td><td valign="bottom">计算以10为基数的对数</td><td valign="bottom">math.log10(100) </td><td valign="bottom">2</td></tr><tr><td>log</td><td valign="bottom">计算一个数字的自然对数</td><td valign="bottom">math.log(2.71)</td><td valign="bottom">0.9969</td></tr><tr><td>max</td><td valign="bottom">取得参数中最大值</td><td valign="bottom">math.max(2.71, 100, -98, 23)</td><td valign="bottom">100</td></tr><tr><td>min</td><td valign="bottom">取得参数中最小值</td><td valign="bottom">math.min(2.71, 100, -98, 23)</td><td valign="bottom">-98</td></tr><tr><td>modf</td><td valign="bottom">把数分为整数和小数</td><td valign="bottom">math.modf(15.98)</td><td valign="bottom">15 98</td></tr><tr><td>pow</td><td valign="bottom">得到x的y次方</td><td valign="bottom">math.pow(2, 5)</td><td valign="bottom">32</td></tr><tr><td>rad</td><td valign="bottom">角度转弧度</td><td valign="bottom">math.rad(180)</td><td valign="bottom">3.14159265358</td></tr><tr><td>random</td><td valign="bottom">获取随机数</td><td valign="bottom">math.random(1, 100) math.random(100)</td><td valign="bottom">获取1-100的随机数</td></tr><tr><td>randomseed</td><td valign="bottom">设置随机数种子</td><td valign="bottom">math.randomseed(os.time())</td><td valign="bottom">在使用math.random函数之前必须使用此函数设置随机数种子</td></tr><tr><td>sinh</td><td valign="bottom">双曲线正弦函数</td><td valign="bottom">math.sinh(0.5)</td><td valign="bottom">0.5210953</td></tr><tr><td>sin</td><td valign="bottom">正弦函数</td><td valign="bottom">math.sin(math.rad(30))</td><td valign="bottom">0.5</td></tr><tr><td>sqrt</td><td valign="bottom">开平方函数</td><td valign="bottom">math.sqrt(16)</td><td valign="bottom">4</td></tr><tr><td>tanh</td><td valign="bottom">双曲线正切函数</td><td valign="bottom">math.tanh(0.5)</td><td valign="bottom">0.46211715</td></tr><tr><td>tan</td><td valign="bottom">正切函数</td><td valign="bottom">math.tan(0.5)</td><td valign="bottom">0.5463024</td></tr></tbody></table> 引用博客:http://www.cnblogs.com/whiteyun/archive/2009/08/10/1543040.html