How to Fix the “Dot indexing not supported for variables of this type” Error in MATLAB

I am writing a code and i've tried to run it. However, it shows me an error saying "Dot indexing is not supported for variables of this type".

Dot indexing is not supported for variables of this type.
Error in SDE (line 38)
dataset = dataset.Train;

Any kind of help will be appreciated. Thank you.

dataset = load(['/Users/zachary/Desktop/MatlabCode/SDE-master/train/',p_name]);
dataset = dataset.Train;
feat = dataset(:,1:end-1); 
labels = dataset(:,end);

[Fabio Freschi]

dataset is not a struct? difficult to say without the file you are loading

[Dyuman Joshi]

It seems the variable dataset is not a struct nor a table, thus using dot indexing gives an error.

It would be helpful if you can attach the file.

[Aedy Vader]

This is the file that you've asked for.

[Dyuman Joshi]

This is just a numeric text file. No headers or anything, just plain numbers. The output will be a numeric array when you read the data in the file with load.

Additionally, the input to load() does not contain the filename (including the extension). Why does it not?

And what are you trying to obtain from the data?

(Also, Are you related to Darth Vader? :P)

Answer 1

[dpb]

That's just a plain text file; use readmatrix to bring it in as an array...

% first read as text to be certain of file structure -- lines are wrapped in browser
l=readlines('QSARbiodegradation.txt');
l(1:5)

ans = 5×1 string array
    "  5.3030000e+000  4.0516000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  1.0000000e+000  0.0000000e+000  2.6100000e+001  4.0000000e+000  3.0000000e+000  0.0000000e+000  0.0000000e+000  3.0100000e+000  1.3920000e+000  1.0053000e+001  9.0000000e+000  1.0070000e+000  1.1540000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  1.0790000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  2.2360000e+000  4.4000000e-002  0.0000000e+000  0.0000000e+000  1.1640000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  3.0000000e+000  3.3200000e+000  3.0280000e+000  0.0000000e+000  7.4530000e+000  0.0000000e+000  0.0000000e+000  2.0000000e+000"
    "  4.4990000e+000  2.9058000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  1.0000000e+000  4.3800000e+001  1.0000000e+000  1.0000000e+000  0.0000000e+000  0.0000000e+000  2.9900000e+000  1.1250000e+000  9.3110000e+000  2.0000000e+000  9.9100000e-001  1.1170000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  1.2430000e+000  1.0000000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  2.1360000e+000  4.4000000e-002  0.0000000e+000  0.0000000e+000  1.4810000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  1.0000000e+000  3.5560000e+000  2.3960000e+000  0.0000000e+000  7.8450000e+000  0.0000000e+000  0.0000000e+000  1.0000000e+000"
    "  5.0130000e+000  1.8267000e+000  2.0000000e+000  1.0000000e+000  1.6000000e+001  0.0000000e+000  7.0000000e+000  4.2400000e+001  2.0000000e+000  5.0000000e+000  1.4000000e+001 -1.1230000e+000  4.6920000e+000  1.5410000e+000  1.1371000e+001  5.0000000e+000  1.0190000e+000  1.1210000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  1.2770000e+000  5.0000000e+000  0.0000000e+000  1.0000000e+000  0.0000000e+000  2.4150000e+000  0.0000000e+000  0.0000000e+000  3.5613000e+001  4.3740000e+000  0.0000000e+000  4.0000000e+000  1.3000000e+001  1.0000000e+000  4.3040000e+000  2.4440000e+000  5.0000000e+000  9.9560000e+000  0.0000000e+000  1.0000000e+000  2.0000000e+000"
    "  4.9710000e+000  3.0393000e+000  0.0000000e+000  0.0000000e+000  2.0000000e+000  0.0000000e+000  2.0000000e+000  3.8700000e+001  3.0000000e+000  1.0000000e+000  2.0000000e+000  1.2400000e-001  3.5090000e+000  1.7330000e+000  1.0236000e+001  4.0000000e+000  9.8400000e-001  1.1300000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  1.2510000e+000  1.0000000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  2.3050000e+000  1.0000000e-003  0.0000000e+000  1.1885000e+001  2.5850000e+000  0.0000000e+000  0.0000000e+000  3.0000000e+000  0.0000000e+000  3.7250000e+000  2.2140000e+000  1.0000000e+000  8.4400000e+000  0.0000000e+000  0.0000000e+000  2.0000000e+000"
    "  5.3610000e+000  1.8900000e+000  0.0000000e+000  0.0000000e+000  2.0000000e+000  1.0000000e+000  0.0000000e+000  2.8900000e+001  2.0000000e+000  4.0000000e+000  2.0000000e+000  0.0000000e+000  3.7640000e+000  1.5910000e+000  1.0691000e+001  1.6000000e+001  1.0030000e+000  1.1510000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  1.1320000e+000  2.0000000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  2.4070000e+000  0.0000000e+000  0.0000000e+000  0.0000000e+000  3.2610000e+000  0.0000000e+000  0.0000000e+000  2.0000000e+000  4.0000000e+000  3.4950000e+000  2.1540000e+000  2.0000000e+000  8.3250000e+000  0.0000000e+000  0.0000000e+000  2.0000000e+000"

And, indeed, that is so..

data=readmatrix('QSARbiodegradation.txt');      % read the array
data(1:5,:)

ans = 5×42

5.3030 4.0516 0 0 0 1.0000 0 26.1000 4.0000 3.0000 0 0 3.0100 1.3920 10.0530 9.0000 1.0070 1.1540 0 0 0 1.0790 0 0 0 0 2.2360 0.0440 0 0 4.4990 2.9058 0 0 0 0 1.0000 43.8000 1.0000 1.0000 0 0 2.9900 1.1250 9.3110 2.0000 0.9910 1.1170 0 0 0 1.2430 1.0000 0 0 0 2.1360 0.0440 0 0 5.0130 1.8267 2.0000 1.0000 16.0000 0 7.0000 42.4000 2.0000 5.0000 14.0000 -1.1230 4.6920 1.5410 11.3710 5.0000 1.0190 1.1210 0 0 0 1.2770 5.0000 0 1.0000 0 2.4150 0 0 35.6130 4.9710 3.0393 0 0 2.0000 0 2.0000 38.7000 3.0000 1.0000 2.0000 0.1240 3.5090 1.7330 10.2360 4.0000 0.9840 1.1300 0 0 0 1.2510 1.0000 0 0 0 2.3050 0.0010 0 11.8850 5.3610 1.8900 0 0 2.0000 1.0000 0 28.9000 2.0000 4.0000 2.0000 0 3.7640 1.5910 10.6910 16.0000 1.0030 1.1510 0 0 0 1.1320 2.0000 0 0 0 2.4070 0 0 0

whos data

  Name        Size             Bytes  Class     Attributes

  data      739x42            248304  double              

No "dot" referencing needed (or allowed). If there are meaningful variable names for each column, then you could use those and either use array2table and assign those or go directly to the table with readtable. However, with 42 columns, it's probably not a particularly convenient data set to use named column variables...

Answer 2

[Walter Roberson]

load() of a .txt file never results in a struct or object so you cannot use dot indexing with it. (well, except if you use the -mat option and the .txt file happened to be mat file format)

load() of a .mat file stored to a file results in a struct -- but not of a .txt

importdata() of a .txt file results in a pure numeric matrix if the txt file has no text headers. But if it has text headers then importdata() can return a struct with a few different possible fields (that are not always going to be present.) Because of this variability in what data type impordata() can return, I recommend against using importdata()