Python Numpy recarray.tolist()函数
在numpy中,数组可以有一个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是一对(int, float)。通常情况下,这些属性使用字典查询,如arr[‘a’] 和arr[‘b’] 。
numpy.recarray.tolist()函数被用来将数组作为一个(可能是嵌套的)列表,它返回一个作为(嵌套的)Python列表的数组数据副本。数据项被转换为最接近的兼容Python类型。
语法: numpy.recarray.tolist()
参数:
None
返回: [list] 可能嵌套的数组元素列表。
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)
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 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:
我们正在对整个记录数组应用numpy.recarray.tolist()。
# 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)
输出:
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)]]