Numpy recarray.ptp()函数| Python
原文:https://www . geesforgeks . org/numpy-recarray-PTP-function-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)]，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来访问的，例如arr['a'] and arr['b']。使用arr.a and arr.b，记录数组允许字段作为数组的成员被访问。
numpy.recarray.ptp() 函数返回沿给定轴的峰值到峰值(最大–最小)值。
语法:
numpy.recarray.ptp(axis=None, out=None)参数:
轴:【int，可选】查找波峰的轴。默认情况下，展平阵列。 出:【可选】存储结果的位置。 - >如果提供，它必须具有输入广播到的形状。 - >如果未提供或无，则返回新分配的阵列。
返回:【ndarray】保存结果的新数组，除非指定了 out，在这种情况下，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)
Output:
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
