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.swapaxes() function return a view of the array with axis1 and axis2 interchanged.
Syntax :
numpy.recarray.swapaxes(axis1, axis2)Parameters:
axis1 : [int] First axis.
axis2 : [int] Second axis.Return : [ndarray] Resultant array.
Code #1 :
# Python program explaining # numpy.recarray.swapaxes() 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.swapaxes methods # to float record array taking axis1 = 0 and axis2 = 1 out_arr = rec_arr.a.swapaxes(0, 1) print ("Output float array : ", out_arr) # applying recarray.swapaxes methods # to int record array taking axis1 = 1 and axis2 = 0 out_arr = rec_arr.b.swapaxes(1, 0) print ("Output int 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 float array : [[ 5. 9.] [ 3. 5.] [ 6. -12.]] Output int array : [[ 2 1] [-4 4] [ 9 -7]]
Code #2 :
We are applying numpy.recarray.swapaxes() to whole record array.
# Python program explaining # numpy.recarray.swapaxes() 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.swapaxes methods to # record array taking axis1 = 0 and axis2 = 1 out_arr = rec_arr.swapaxes(1, 0) print ("Output record array : ", out_arr) |
Output:
Input array : [[( 5., 2) ( 3., 4) ( 6., -7)] [( 9., 1) ( 6., 4) (-2., -7)]] Output record array : [[( 5., 2) ( 9., 1)] [( 3., 4) ( 6., 4)] [( 6., -7) (-2., -7)]]
