📅 最后修改于: 2020-11-08 07:38:09 🧑 作者: Mango
可以理解，NumPy包含大量的各种数学运算。 NumPy提供标准的三角函数，用于算术运算，处理复数的函数等。
NumPy具有标准的三角函数，对于给定的角度(弧度)返回三角比例。
例
import numpy as np
a = np.array([0,30,45,60,90])
print 'Sine of different angles:'
# Convert to radians by multiplying with pi/180
print np.sin(a*np.pi/180)
print '\n'
print 'Cosine values for angles in array:'
print np.cos(a*np.pi/180)
print '\n'
print 'Tangent values for given angles:'
print np.tan(a*np.pi/180)
这是它的输出-
Sine of different angles:
[ 0. 0.5 0.70710678 0.8660254 1. ]
Cosine values for angles in array:
[ 1.00000000e+00 8.66025404e-01 7.07106781e-01 5.00000000e-01
6.12323400e-17]
Tangent values for given angles:
[ 0.00000000e+00 5.77350269e-01 1.00000000e+00 1.73205081e+00
1.63312394e+16]
arcsin，arcos和arctan函数返回给定角度的sin，cos和tan的三角逆。这些函数的结果可以通过numpy.degrees()函数将弧度转换为度来验证。
例
import numpy as np
a = np.array([0,30,45,60,90])
print 'Array containing sine values:'
sin = np.sin(a*np.pi/180)
print sin
print '\n'
print 'Compute sine inverse of angles. Returned values are in radians.'
inv = np.arcsin(sin)
print inv
print '\n'
print 'Check result by converting to degrees:'
print np.degrees(inv)
print '\n'
print 'arccos and arctan functions behave similarly:'
cos = np.cos(a*np.pi/180)
print cos
print '\n'
print 'Inverse of cos:'
inv = np.arccos(cos)
print inv
print '\n'
print 'In degrees:'
print np.degrees(inv)
print '\n'
print 'Tan function:'
tan = np.tan(a*np.pi/180)
print tan
print '\n'
print 'Inverse of tan:'
inv = np.arctan(tan)
print inv
print '\n'
print 'In degrees:'
print np.degrees(inv)
其输出如下-
Array containing sine values:
[ 0. 0.5 0.70710678 0.8660254 1. ]
Compute sine inverse of angles. Returned values are in radians.
[ 0. 0.52359878 0.78539816 1.04719755 1.57079633]
Check result by converting to degrees:
[ 0. 30. 45. 60. 90.]
arccos and arctan functions behave similarly:
[ 1.00000000e+00 8.66025404e-01 7.07106781e-01 5.00000000e-01
6.12323400e-17]
Inverse of cos:
[ 0. 0.52359878 0.78539816 1.04719755 1.57079633]
In degrees:
[ 0. 30. 45. 60. 90.]
Tan function:
[ 0.00000000e+00 5.77350269e-01 1.00000000e+00 1.73205081e+00
1.63312394e+16]
Inverse of tan:
[ 0. 0.52359878 0.78539816 1.04719755 1.57079633]
In degrees:
[ 0. 30. 45. 60. 90.]
此函数返回四舍五入到所需精度的值。该函数采用以下参数。
numpy.around(a,decimals)
哪里，
| Sr.No. | Parameter & Description |
|---|---|
| 1 |
a Input data |
| 2 |
decimals The number of decimals to round to. Default is 0. If negative, the integer is rounded to position to the left of the decimal point |
例
import numpy as np
a = np.array([1.0,5.55, 123, 0.567, 25.532])
print 'Original array:'
print a
print '\n'
print 'After rounding:'
print np.around(a)
print np.around(a, decimals = 1)
print np.around(a, decimals = -1)
产生以下输出-
Original array:
[ 1. 5.55 123. 0.567 25.532]
After rounding:
[ 1. 6. 123. 1. 26. ]
[ 1. 5.6 123. 0.6 25.5]
[ 0. 10. 120. 0. 30. ]
此函数返回不大于输入参数的最大整数。标量x的下限是最大整数i ，使得i <= x 。请注意，在Python，下限始终从0舍入。
例
import numpy as np
a = np.array([-1.7, 1.5, -0.2, 0.6, 10])
print 'The given array:'
print a
print '\n'
print 'The modified array:'
print np.floor(a)
产生以下输出-
The given array:
[ -1.7 1.5 -0.2 0.6 10. ]
The modified array:
[ -2. 1. -1. 0. 10.]
ceil()函数返回输入值的上限，即标量x的ceil是最小的整数i ，使得i> = x。
例
import numpy as np
a = np.array([-1.7, 1.5, -0.2, 0.6, 10])
print 'The given array:'
print a
print '\n'
print 'The modified array:'
print np.ceil(a)
它将产生以下输出-
The given array:
[ -1.7 1.5 -0.2 0.6 10. ]
The modified array:
[ -1. 2. -0. 1. 10.]