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Numpy recarray.tostring()函数| Python

原文:https://www . geesforgeks . org/numpy-recarray-tostring-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']

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.tostring() 函数构造包含数组中原始数据字节的 Python 字节。

语法: numpy.recarray.tostring(order='C')

参数: 顺序: ['C ',' F ',无,可选]多维数组的数据顺序:C,Fortran,或与原始数组相同。

返回:【字节】显示记录数组原始数据副本的 Python 字节。

代码#1 :

# Python program explaining
# numpy.recarray.tostring() 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.tostring methods
# to float record array in default order
out_arr = rec_arr.a.tostring()
print ("Output Python bytes of float record array in default order ", out_arr) 
print()

# applying recarray.tostring methods
# to float record array in fortan order
out_arr = rec_arr.a.tostring(order ='F')
print ("Output Python bytes of float record array in fortan order ", out_arr) 
print()

# applying recarray.tostring methods 
# to int record array in default order
out_arr = rec_arr.b.tostring()
print ("Output Python bytes of int record array in default order ", out_arr) 
print()

# applying recarray.tostring methods 
# to int record array in fortan order
out_arr = rec_arr.b.tostring(order ='F')
print ("Output Python bytes of int record array in fortan order ", out_arr) 

Output:

输入数组:[[( 5。, 2) ( 3., -4) ( 6.,9)】 【(9。, 1) ( 5., 4) (-12.,-7)] 记录数组的 float: [[ 5。3.6.】 【9。5.-12.] int 的记录数组:[[ 2 -4 9] [ 1 4 -7]] 以默认顺序 b '输出浮点记录数组的 Python 字节\ x00 \ x00 \ x00 \ x00 \ x00 \ x14 @ \ x00 \ x00 \ x00 \ x00 \ x00 \ x08 @ \ x00 \ x00 \ x00 \ x00 \ x00 \ x00 \ x18 @ \ x00 \ x00 \ x00 \ x00 \

以 b '的顺序输出浮点记录数组的 Python 字节\ x00 \ x00 \ x00 \ x00 \ x00 \ x14 @ \ x00 \ x00 \ x00 \ x00 \ x00 “@ \ x00 \ x00 \ x00 \ x00 \ x08 @ \ x00 \ x00 \ x00 \ x00 \ x14 @ \ x00 \ x00 \ x00 \ x00 \ x00 \ x00 \ x00 \ x00 \ x18 @ \ x00 \ x00

按默认顺序输出 int 记录数组的 Python 字节 b ' \ x02 \ x00 \ x00 \ x00 \ xfc \ xff \ xff \ xff \ t \ x00 \ x00 \ x00 \ x01 \ x00 \ x00 \ x04 \ x00 \ x00 \ x00 \ xf9 \ xff \ xff \ xff \ xff \ xff '

按顺序 b '输出 int 记录数组的 Python 字节\ x02 \ x00 \ x00 \ x00 \ x01 \ x00 \ x00 \ x00 \ xfc \ xff \ xff \ xff \ x04 \ x00 \ x00 \ t \ x00 \ x00 \ x00 \ xf9 \ xff \ xff \ xff '

代码#2 :

我们将numpy.recarray.tostring()应用于整个记录数组。

# Python program explaining
# numpy.recarray.tostring() 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, -7)],
                     [(9.0, 1), (6.0, 4), (-2.0, -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)

# applying recarray.tostring methods to  
# record array in default order
out_arr = rec_arr.tostring()
print ("Output Python bytes of record array in default order ", out_arr) 
print()

# applying recarray.tostring methods to  
# record array in fortan order
out_arr = rec_arr.tostring(order ='F')
print ("Output Python bytes of record array in fortan order ", out_arr) 

Output:

输入数组:[( 5,2) ( 3,4) ( 6,-7)] [(9,1) ( 6,4) (-2,-7)]] 默认顺序 b 中记录数组 Python 字节的输出:\ 0x 00 \ 0x 00 \ 0x 00 \ x 00 \ x 00 \ x 00 \ x 14 @ \ x02 \ x 00 \ x 00 \ x 00 \ x 00 \ x 00 \ x 00 \ x 00 \ x 00 \ x 00 \ x 00 \ x 00 \ x 00 \ x 00 \ x 08 @ \ x4 \ x

Python 输出记录数组字节,位于 fortan order b ' \ 0x 00 \ 0x 00 \ x0 \ x 00 \ x14 @ \ x02 \ 0x 00 \ 0x 00 \ 0x 00 \ 0x 00 \ 0x 00 \ 0x 00 \ 0x 00 \ 0x 00 @ \ x01 \ 0x 00 \ 0x 00 \ 0x 00 \ 0x 00 \ 0x 00 \ 0x 00 \ 0x 00 \ 0x 00 \ 0x 00 \ 0x 08 @ \ x04 \ 0x 00 \ 0x 00 \ 0x 00 \ 0x 00 \ 0x 00 \ x 00 \ x 00 00 \ x 00 00 00 \ x 00 00



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