Python Numpy recarray.max()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.max()函数返回记录数组的最大值或沿轴的最大值。

用法： numpy.recarray.max(axis=None, out=None, keepdims=False)

参数：
axis :[无，整数或整数元组，可选]沿其运行的一个或多个轴。默认情况下，使用拼合的输入。
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。
keepdims :[布尔，可选]如果将其设置为True，则缩小的轴将保留为尺寸为1的尺寸。使用此选项，结果将针对输入数组正确广播。

Return :[ndarray或标量]记录数组的最大值。如果axis为None，则结果为标量值。如果给定axis，则结果是尺寸为arr.ndim-1的数组。

代码1：

# Python program explaining 
# numpy.recarray.max() 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, 8)], 
                     [(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.max methods 
# to float record array along default axis  
# i, e along flattened array 
out_arr1 = rec_arr.a.max() 
# Maximum of the flattened array  
print("\nMax of float record array, axis = None:", out_arr1)  
  
  
# applying recarray.max methods 
# to float record array along axis 0 
# i, e along vertical 
out_arr2 = rec_arr.a.max(axis = 0) 
# Maximum along 0 axis 
print("\nMax of float record array, axis = 0:", out_arr2) 
  
  
# applying recarray.max methods 
# to float record array along axis 1 
# i, e along horizontal 
out_arr3 = rec_arr.a.max(axis = 1) 
# Maximum along 0 axis 
print("\nMax of float record array, axis = 1:", out_arr3) 
  
  
# applying recarray.max methods 
# to int record array along default axis  
# i, e along flattened array 
out_arr4 = rec_arr.b.max() 
# Maximum of the flattened array  
print("\nMax of int record array, axis = None:", out_arr4)  
  
  
# applying recarray.max methods 
# to int record array along axis 0 
# i, e along vertical 
out_arr5 = rec_arr.b.max(axis = 0) 
# Maximum along 0 axis 
print("\nMax of int record array, axis = 0:", out_arr5) 
  
  
# applying recarray.max methods 
# to int record array along axis 1 
# i, e along horizontal 
out_arr6 = rec_arr.b.max(axis = 1) 
# Maximum along 0 axis 
print("\nMax of int record array, axis = 1:", out_arr6)

输出：

Input array: [[(  5.,  2) (  3., -4) (  6.,  8)]
 [(  9.,  1) (  5.,  4) (-12., -7)]]
Record array of float: [[  5.   3.   6.]
 [  9.   5. -12.]]
Record array of int: [[ 2 -4  8]
 [ 1  4 -7]]

Max of float record array, axis = None: 9.0

Max of float record array, axis = 0: [9. 5. 6.]

Max of float record array, axis = 1: [6. 9.]

Max of int record array, axis = None: 8

Max of int record array, axis = 0: [2 4 8]

Max of int record array, axis = 1: [8 4]

相关用法

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.max() 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。