numpy ufunc |通用功能

Numpy 中的通用函数是简单的数学函数。这只是我们在 Numpy 库中赋予数学函数的一个术语。 Numpy 提供了涵盖各种操作的各种通用函数。
这些函数包括标准三角函数、算术运算函数、处理复数、统计函数等。通用函数具有以下各种特性：

• 这些函数在ndarray （N 维数组）上运行，即 Numpy 的数组类。
• 它执行快速的元素数组操作。
• 它支持各种功能，如数组广播、类型转换等。
• Numpy，通用函数是属于 numpy.ufunc 类的对象。
• Python函数也可以使用frompyfunc库函数。
• 当在数组上使用相应的算术运算符时，会自动调用一些ufunc 。例如，当使用 '+'运算符按元素执行两个数组的相加时，会在内部调用 np.add()。

Numpy 中的一些基本通用功能是 -

三角函数：

这些函数适用于弧度，因此需要通过乘以 pi/180 将角度转换为弧度。只有这样我们才能调用三角函数。它们将数组作为输入参数。它包括以下功能 -

Function	Description
sin, cos, tan	compute sine, cosine and tangent of angles
arcsin, arccos, arctan	calculate inverse sine, cosine and tangent
hypot	calculate hypotenuse of given right triangle
sinh, cosh, tanh	compute hyperbolic sine, cosine and tangent
arcsinh, arccosh, arctanh	compute inverse hyperbolic sine, cosine and tangent
deg2rad	convert degree into radians
rad2deg	convert radians into degree

Python3

# Python code to demonstrate trigonometric function
import numpy as np
  
# create an array of angles
angles = np.array([0, 30, 45, 60, 90, 180]) 
  
# conversion of degree into radians
# using deg2rad function
radians = np.deg2rad(angles)
  
# sine of angles
print('Sine of angles in the array:')
sine_value = np.sin(radians)
print(np.sin(radians))
  
# inverse sine of sine values
print('Inverse Sine of sine values:')
print(np.rad2deg(np.arcsin(sine_value)))
  
# hyperbolic sine of angles
print('Sine hyperbolic of angles in the array:')
sineh_value = np.sinh(radians)
print(np.sinh(radians))
  
# inverse sine hyperbolic 
print('Inverse Sine hyperbolic:')
print(np.sin(sineh_value)) 
  
# hypot function demonstration
base = 4
height = 3
print('hypotenuse of right triangle is:')
print(np.hypot(base, height))

输出：

Sine of angles in the array:
[  0.00000000e+00   5.00000000e-01   7.07106781e-01   8.66025404e-01
   1.00000000e+00   1.22464680e-16]

Inverse Sine of sine values:
[  0.00000000e+00   3.00000000e+01   4.50000000e+01   6.00000000e+01
   9.00000000e+01   7.01670930e-15]

Sine hyperbolic of angles in the array:
[  0.           0.54785347   0.86867096   1.24936705   2.3012989
  11.54873936]

Inverse Sine hyperbolic:
[ 0.          0.52085606  0.76347126  0.94878485  0.74483916 -0.85086591]

hypotenuse of right triangle is:
5.0

统计功能：

这些函数用于计算数组元素的均值、中值、方差、最小值。它包括以下功能 -

Function	Description
amin, amax	returns minimum or maximum of an array or along an axis
ptp	returns range of values (maximum-minimum) of an array or along an axis
percentile(a, p, axis)	calculate pth percentile of array or along specified axis
median	compute median of data along specified axis
mean	compute mean of data along specified axis
std	compute standard deviation of data along specified axis
var	compute variance of data along specified axis
average	compute average of data along specified axis

Python3

# Python code demonstrate statistical function
import numpy as np
  
# construct a weight array
weight = np.array([50.7, 52.5, 50, 58, 55.63, 73.25, 49.5, 45])
  
# minimum and maximum 
print('Minimum and maximum weight of the students: ')
print(np.amin(weight), np.amax(weight))
  
# range of weight i.e. max weight-min weight
print('Range of the weight of the students: ')
print(np.ptp(weight))
  
# percentile
print('Weight below which 70 % student fall: ')
print(np.percentile(weight, 70))
   
# mean 
print('Mean weight of the students: ')
print(np.mean(weight))
  
# median 
print('Median weight of the students: ')
print(np.median(weight))
  
# standard deviation 
print('Standard deviation of weight of the students: ')
print(np.std(weight))
  
# variance 
print('Variance of weight of the students: ')
print(np.var(weight))
  
# average 
print('Average weight of the students: ')
print(np.average(weight))

输出：

Minimum and maximum weight of the students: 
45.0 73.25

Range of the weight of the students: 
28.25

Weight below which 70 % student fall: 
55.317

Mean weight of the students: 
54.3225

Median weight of the students: 
51.6

Standard deviation of weight of the students: 
8.05277397857

Variance of weight of the students: 
64.84716875

Average weight of the students: 
54.3225

位旋转功能：

这些函数接受整数值作为输入参数，并对这些整数的二进制表示执行按位运算。它包括以下功能 -

Function	Description
bitwise_and	performs bitwise and operation on two array elements
bitwies_or	performs bitwise or operation on two array elements
bitwise_xor	performs bitwise xor operation on two array elements
invert	performs bitwise inversion of an array elements
left_shift	shift the bits of elements to left
right_shift	shift the bits of elements to left

Python3

# Python code to demonstrate bitwise-function
import numpy as np
  
# construct an array of even and odd numbers
even = np.array([0, 2, 4, 6, 8, 16, 32])
odd = np.array([1, 3, 5, 7, 9, 17, 33])
  
# bitwise_and
print('bitwise_and of two arrays: ')
print(np.bitwise_and(even, odd))
  
# bitwise_or
print('bitwise_or of two arrays: ')
print(np.bitwise_or(even, odd))
  
# bitwise_xor
print('bitwise_xor of two arrays: ')
print(np.bitwise_xor(even, odd))
   
# invert or not
print('inversion of even no. array: ')
print(np.invert(even))
  
# left_shift 
print('left_shift of even no. array: ')
print(np.left_shift(even, 1))
  
# right_shift 
print('right_shift of even no. array: ')
print(np.right_shift(even, 1))

输出：

bitwise_and of two arrays: 
[ 0  2  4  6  8 16 32]

bitwise_or of two arrays: 
[ 1  3  5  7  9 17 33]

bitwise_xor of two arrays: 
[1 1 1 1 1 1 1]

inversion of even no. array: 
[ -1  -3  -5  -7  -9 -17 -33]

left_shift of even no. array: 
[ 0  4  8 12 16 32 64]

right_shift of even no. array: 
[ 0  1  2  3  4  8 16]