Python Numpy recarray.ptp()用法及代码示例

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，这些属性是使用字典查找(例如，arr['a'] and arr['b']。记录数组允许使用以下方式将字段作为数组的成员进行访问arr.a and arr.b。

numpy.recarray.ptp()函数沿给定轴返回“峰到峰”(最大值-最小值)值。

用法： numpy.recarray.ptp(axis=None, out=None)

参数：

axis : [int，可选]沿其查找峰的轴。默认情况下，展平阵列。
out : [ndarray，可选]将结果存储到的位置。
->如果提供，则必须具有广播输入的形状。
->如果未提供或没有，则返回新分配的数组。

返回：[ndarray]保存结果的新数组，除非指定了out，否则将返回对out的引用。

代码1：

# Python program explaining 
# numpy.recarray.ptp() 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.ptp methods 
# to float record array along axis 1 
out_arr = rec_arr.a.ptp( axis = 1) 
print ("Output range array of float along axis 1: ", out_arr)  
  
# applying recarray.ptp methods 
# to float record array along axis 0 
out_arr = rec_arr.a.ptp( axis = 0) 
print ("Output range array of float along axis 0: ", out_arr)  
  
# applying recarray.ptp methods 
# to float record array along -1 axis  
out_arr = rec_arr.a.ptp( axis = -1) 
print ("Output range array of float along -1 axis : ", out_arr)  
  
# applying recarray.ptp methods  
# to int record array along default axis value 
out_arr = rec_arr.a.ptp() 
print ("Output range of float array elements array along default axis: ", out_arr)  
  
  
# applying recarray.ptp methods 
# to int record array along axis 1 
out_arr = rec_arr.b.ptp( axis = 1) 
print ("Output range array of int along axis 1: ", out_arr)  
  
# applying recarray.ptp methods 
# to int record array along axis 0 
out_arr = rec_arr.b.ptp( axis = 0) 
print ("Output range array of int along axis 0: ", out_arr)  
  
# applying recarray.ptp methods 
# to int record array along -1 axis  
out_arr = rec_arr.b.ptp( axis = -1) 
print ("Output range array of int along -1 axis : ", out_arr)  
  
  
# applying recarray.ptp methods  
# to int record array along default axis value 
out_arr = rec_arr.b.ptp() 
print ("Output range 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 range array of float along axis 1:  [ 3. 21.]
Output range array of float along axis 0:  [ 4.  2. 18.]
Output range array of float along -1 axis :  [ 3. 21.]
Output range of float array elements array along default axis:  21.0
Output range array of int along axis 1:  [13 11]
Output range array of int along axis 0:  [ 1  8 16]
Output range array of int along -1 axis :  [13 11]
Output range of int array elements array along default axis:  16

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注：本文由纯净天空筛选整理自jana_sayantan大神的英文原创作品 Numpy recarray.ptp() function | Python。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。