python中math模块常用的方法整理
ceil:取大于等于x的最小的整数值，如果x是一个整数，则返回x
copysign:把y的正负号加到x前面，可以使用0
cos:求x的余弦，x必须是弧度
degrees:把x从弧度转换成角度
e:表示一个常量
exp:返回math.e,也就是2.71828的x次方
expm1:返回math.e的x(其值为2.71828)次方的值减１
fabs:返回x的绝对值
factorial:取x的阶乘的值
floor:取小于等于x的整数值，如果x是一个整数，则返回自身
fmod:得到x/y的余数，其值是一个浮点数
frexp:返回一个元组(m,e),其计算方式为：x分别除0.5和1,得到一个值的范围
fsum:对迭代器里的每个元素进行求和操作
gcd:返回x和y的公约数
hypot:如果x是不是无穷大的数字,则返回True,否则返回False
isfinite:如果x是正无穷大或负无穷大，则返回True,否则返回False
isinf:如果x是正无穷大或负无穷大，则返回True,否则返回False
isnan:如果x不是数字True,否则返回False
ldexp:返回x*(2**i)的值
log:返回x的自然对数，默认以e为基数，base参数给定时，将x的对数返回给定的base,计算式为：log(x)/log(base)
log10:返回x的以10为底的对数
log1p:返回x+1的自然对数(基数为e)的值
log2:返回x的基2对数
modf:返回由x的小数部分和整数部分组成的元组
pi:数字常量，圆周率
pow:返回x的y次方，即x**y
radians:把角度x转换成弧度
sin:求x(x为弧度)的正弦值
sqrt:求x的平方根
tan:返回x(x为弧度)的正切值
trunc:返回x的整数部分
ceil
#取大于等于x的最小的整数值，如果x是一个整数，则返回x ceil(x) Return the ceiling of x as an int. This is the smallest integral value >= x.>>> math.ceil(4.01) 5 >>> math.ceil(4.99) 5 >>> math.ceil(-3.99) -3 >>> math.ceil(-3.01) -3
copysign
#把y的正负号加到x前面，可以使用0 copysign(x, y) Return a float with the magnitude (absolute value) of x but the sign of y. On platforms that support signed zeros, copysign(1.0, -0.0) returns -1.0.>>> math.copysign(2,3) 2.0 >>> math.copysign(2,-3) -2.0 >>> math.copysign(3,8) 3.0 >>> math.copysign(3,-8) -3.0
cos
#求x的余弦，x必须是弧度 cos(x) Return the cosine of x (measured in radians).#math.pi/4表示弧度，转换成角度为45度 >>> math.cos(math.pi/4) 0.7071067811865476 math.pi/3表示弧度，转换成角度为60度 >>> math.cos(math.pi/3) 0.5000000000000001 math.pi/6表示弧度，转换成角度为30度 >>> math.cos(math.pi/6) 0.8660254037844387
degrees
#把x从弧度转换成角度 degrees(x) Convert angle x from radians to degrees.>>> math.degrees(math.pi/4) 45.0 >>> math.degrees(math.pi) 180.0 >>> math.degrees(math.pi/6) 29.999999999999996 >>> math.degrees(math.pi/3) 59.99999999999999
e
#表示一个常量>>> math.e 2.718281828459045
exp
#返回math.e,也就是2.71828的x次方 exp(x) Return e raised to the power of x.>>> math.exp(1) 2.718281828459045 >>> math.exp(2) 7.38905609893065 >>> math.exp(3) 20.085536923187668
expm1
#返回math.e的x(其值为2.71828)次方的值减１ expm1(x) Return exp(x)-1. This function avoids the loss of precision involved in the direct evaluation of exp(x)-1 for small x.>>> math.expm1(1) 1.718281828459045 >>> math.expm1(2) 6.38905609893065 >>> math.expm1(3) 19.085536923187668
fabs
#返回x的绝对值 fabs(x) Return the absolute value of the float x.>>> math.fabs(-0.003) 0.003 >>> math.fabs(-110) 110.0 >>> math.fabs(100) 100.0
factorial
#取x的阶乘的值 factorial(x) -> Integral Find x!. Raise a ValueError if x is negative or non-integral.>>> math.factorial(1) 1 >>> math.factorial(2) 2 >>> math.factorial(3) 6 >>> math.factorial(5) 120 >>> math.factorial(10) 3628800
floor
#取小于等于x的整数值，如果x是一个整数，则返回自身 floor(x) Return the floor of x as an int. This is the largest integral value <= x.>>> math.floor(4.1) 4 >>> math.floor(4.999) 4 >>> math.floor(-4.999) -5 >>> math.floor(-4.01) -5
fmod
#得到x/y的余数，其值是一个浮点数 fmod(x, y) Return fmod(x, y), according to platform C. x % y may differ.>>> math.fmod(20,3) 2.0 >>> math.fmod(20,7) 6.0
frexp
#返回一个元组(m,e),其计算方式为：x分别除0.5和1,得到一个值的范围， #2**e的值在这个范围内，e取符合要求的整数值,然后x/(2**e),得到m的值 #如果x等于0,则m和e的值都为0,m的绝对值的范围为(0.5,1)之间，不包括0.5和1 frexp(x) Return the mantissa and exponent of x, as pair (m, e). m is a float and e is an int, such that x = m * 2.**e. If x is 0, m and e are both 0. Else 0.5 <= abs(m) < 1.0.>>> math.frexp(10) (0.625, 4) >>> math.frexp(75) (0.5859375, 7) >>> math.frexp(-40) (-0.625, 6) >>> math.frexp(-100) (-0.78125, 7) >>> math.frexp(100) (0.78125, 7)
fsum
#对迭代器里的每个元素进行求和操作 fsum(iterable) Return an accurate floating point sum of values in the iterable. Assumes IEEE-754 floating point arithmetic.>>> math.fsum([1,2,3,4]) 10.0 >>> math.fsum((1,2,3,4)) 10.0 >>> math.fsum((-1,-2,-3,-4)) -10.0 >>> math.fsum([-1,-2,-3,-4]) -10.0
gcd
#返回x和y的公约数 gcd(x, y) -> int greatest common divisor of x and y>>> math.gcd(8,6) 2 >>> math.gcd(40,20) 20 >>> math.gcd(8,12) 4
hypot
#得到(x**2+y**2),平方的值 hypot(x, y) Return the Euclidean distance, sqrt(x*x + y*y).>>> math.hypot(3,4) 5.0 >>> math.hypot(6,8) 10.0
isfinite
#如果x是不是无穷大的数字,则返回True,否则返回False isfinite(x) -> bool Return True if x is neither an infinity nor a NaN, and False otherwise.>>> math.isfinite(100) True >>> math.isfinite(0) True >>> math.isfinite(0.1) True >>> math.isfinite("a") >>> math.isfinite(0.0001) True
isinf
#如果x是正无穷大或负无穷大，则返回True,否则返回False isinf(x) -> bool Return True if x is a positive or negative infinity, and False otherwise.>>> math.isinf(234) False >>> math.isinf(0.1) False
isnan
#如果x不是数字True,否则返回False isnan(x) -> bool Return True if x is a NaN (not a number), and False otherwise.>>> math.isnan(23) False >>> math.isnan(0.01) False
ldexp
#返回x*(2**i)的值 ldexp(x, i) Return x * (2**i).>>> math.ldexp(5,5) 160.0 >>> math.ldexp(3,5) 96.0
log
#返回x的自然对数，默认以e为基数，base参数给定时，将x的对数返回给定的base,计算式为：log(x)/log(base) log(x[, base]) Return the logarithm of x to the given base. If the base not specified, returns the natural logarithm (base e) of x.>>> math.log(10) 2.302585092994046 >>> math.log(11) 2.3978952727983707 >>> math.log(20) 2.995732273553991
log10
#返回x的以10为底的对数 log10(x) Return the base 10 logarithm of x.>>> math.log10(10) 1.0 >>> math.log10(100) 2.0 #即10的1.3次方的结果为20 >>> math.log10(20) 1.3010299956639813
log1p
#返回x+1的自然对数(基数为e)的值 log1p(x) Return the natural logarithm of 1+x (base e). The result is computed in a way which is accurate for x near zero.>>> math.log(10) 2.302585092994046 >>> math.log1p(10) 2.3978952727983707 >>> math.log(11) 2.3978952727983707
log2
#返回x的基2对数 log2(x) Return the base 2 logarithm of x.>>> math.log2(32) 5.0 >>> math.log2(20) 4.321928094887363 >>> math.log2(16) 4.0
modf
#返回由x的小数部分和整数部分组成的元组 modf(x) Return the fractional and integer parts of x. Both results carry the sign of x and are floats.>>> math.modf(math.pi) (0.14159265358979312, 3.0) >>> math.modf(12.34) (0.33999999999999986, 12.0)
pi
#数字常量，圆周率>>> print(math.pi) 3.141592653589793pow
#返回x的y次方，即x**y pow(x, y) Return x**y (x to the power of y).>>> math.pow(3,4) 81.0 >>> >>> math.pow(2,7) 128.0
radians
#把角度x转换成弧度 radians(x) Convert angle x from degrees to radians.>>> math.radians(45) 0.7853981633974483 >>> math.radians(60) 1.0471975511965976
sin
#求x(x为弧度)的正弦值 sin(x) Return the sine of x (measured in radians).>>> math.sin(math.pi/4) 0.7071067811865475 >>> math.sin(math.pi/2) 1.0 >>> math.sin(math.pi/3) 0.8660254037844386
sqrt
#求x的平方根 sqrt(x) Return the square root of x.>>> math.sqrt(100) 10.0 >>> math.sqrt(16) 4.0 >>> math.sqrt(20) 4.47213595499958
tan
#返回x(x为弧度)的正切值 tan(x) Return the tangent of x (measured in radians).>>> math.tan(math.pi/4) 0.9999999999999999 >>> math.tan(math.pi/6) 0.5773502691896257 >>> math.tan(math.pi/3) 1.7320508075688767
trunc
#返回x的整数部分 trunc(x:Real) -> Integral Truncates x to the nearest Integral toward 0. Uses the __trunc__ magic method.>>> math.trunc(6.789) 6 >>> math.trunc(math.pi) 3 >>> math.trunc(2.567) 2
