Subscript indices must either be real positive integers or logicals

getting this error when trying to build a set of data from a data store with the following code. I would like for every iteration of the for loop (one read from the data store), to add data to the table.

 if true
 clear
 clc

 ds = fileDatastore(fullfile('***example****);
 tf = hasdata(ds);
 i = 0

 while (tf == 1);
  accData(i,:) = read(ds); %read from datastore
  tf = hasdata(ds);
  i = i+1
 end

thanks in advance

Answer 1

[Image Analyst]

See the FAQ for a full explanation: http://matlab.wikia.com/wiki/FAQ#How_do_I_fix_the_error_.22Subscript_indices_must_either_be_real_positive_integers_or_logicals..22.3F

Answer 2

[Walter Roberson]

You initialize i = 0, and then assign to accData(i,:) which tries to use that 0 as the index. You should do the i = i + 1 before using i as the index.

Answer 3

[Jeremy Hughes]

Very common error. =) MATLAB arrays start at index = 1. You should see the same error from x(0,:) = 1.

In this case, I don't think you need the loop at all. Use the readall function:

accData = readall(ds)