In numpy, arrays may have a data-types containing fields, analogous to columns in a spreadsheet. An example is [(a, int), (b, float)], where each entry in the array is a pair of (int, float). Normally, these attributes are accessed using dictionary lookups such as arr['a'] and arr['b'].
Record arrays allow the fields to be accessed as members of the array, using arr.a and arr.b. numpy.recarray.tolist() function is used to make the array as a (possibly nested) list.It return a copy of the array data as a (nested) Python list. Data items are converted to the nearest compatible Python type.
Syntax :
numpy.recarray.tolist()Parameters:
NoneReturn : [list] The possibly nested list of array elements.
Code #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) |
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]]
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Code #2 :
We are applying numpy.recarray.tolist() to whole record array.
# 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) |
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)]]
