📜  numpy recarray.prod()函数| Python

📅  最后修改于: 2022-05-13 01:55:40.993000             🧑  作者: Mango

numpy recarray.prod()函数| Python

在 numpy 中,数组可能具有包含字段的数据类型,类似于电子表格中的列。一个例子是[(a, int), (b, float)] ,其中数组中的每个条目都是一对 (int, float)。通常,使用诸如arr['a'] and arr['b']类的字典查找来访问这些属性。

记录数组允许使用arr.a and arr.b作为数组成员访问字段。 numpy.recarray.prod()函数返回给定轴上数组元素的乘积。

代码#1:

# Python program explaining
# numpy.recarray.prod() method 
  
# importing numpy as geek
import numpy as geek
  
# creating input array with 2 different field 
in_arr = geek.array([[(5.0, 2), (3.0, -4), (6.0, 9)],
                     [(9.0, 1), (5.0, 4), (-12.0, -7)]],
                     dtype =[('a', float), ('b', int)])
print ("Input array : ", in_arr)
  
# convert it to a record array,
# using arr.view(np.recarray)
rec_arr = in_arr.view(geek.recarray)
print("Record array of float: ", rec_arr.a)
print("Record array of int: ", rec_arr.b)
  
# applying recarray.prod methods
# to float record array along axis 1
out_arr = rec_arr.a.prod( axis = 1)
print ("Output product array of float along axis 1: ", out_arr) 
  
# applying recarray.prod methods
# to float record array along axis 0
out_arr = rec_arr.a.prod( axis = 0)
print ("Output product array of float along axis 0: ", out_arr) 
  
# applying recarray.prod methods
# to float record array along -1 axis 
out_arr = rec_arr.a.prod( axis = -1)
print ("Output product array of float along -1 axis : ", out_arr) 
  
  
# applying recarray.prod methods 
# to int record array along default axis value
out_arr = rec_arr.b.prod()
print ("Output product of int array elements array along default axis: ", out_arr) 
输出:
Input array :  [[(  5.,  2) (  3., -4) (  6.,  9)]
 [(  9.,  1) (  5.,  4) (-12., -7)]]
Record array of float:  [[  5.   3.   6.]
 [  9.   5. -12.]]
Record array of int:  [[ 2 -4  9]
 [ 1  4 -7]]
Output product array of float along axis 1:  [  90. -540.]
Output product array of float along axis 0:  [ 45.  15. -72.]
Output product array of float along -1 axis :  [  90. -540.]
Output product of int array elements array along default axis:  2016