Numpy recarray.tolist()函数| Python
原文:https://www . geeksforgeeks . org/numpy-recarray-to list-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.tolist() 函数用于使数组成为一个(可能是嵌套的)列表。它以(嵌套的)Python 列表的形式返回数组数据的副本。数据项被转换为最近的兼容 Python 类型。
语法:
numpy.recarray.tolist()参数:T2无
返回:【列表】数组元素可能嵌套的列表。
代码#1 :
# Python program explaining
# numpy.recarray.tolist() 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.tolist methods
# to float record array
out_arr = rec_arr.a.tolist()
print ("Output list of float record array ", out_arr)
# applying recarray.tolist methods
# to int record array
out_arr = rec_arr.b.tolist()
print ("Output list of int record array ", 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 list of float record array [[5.0, 3.0, 6.0], [9.0, 5.0, -12.0]]
Output list of int record array [[2, -4, 9], [1, 4, -7]]
代码#2 :
我们将numpy.recarray.tolist()应用于整个记录数组。
# Python program explaining
# numpy.recarray.tolist() 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.tolist methods to
# record array in default order
out_arr = rec_arr.tolist()
print ("Output list of record array ", out_arr)
Output:
Input array : [[( 5., 2) ( 3., 4) ( 6., -7)]
[( 9., 1) ( 6., 4) (-2., -7)]]
Output list of record array [[(5.0, 2), (3.0, 4), (6.0, -7)], [(9.0, 1), (6.0, 4), (-2.0, -7)]]
