How can I transform cell arrays into arrays that allow indexing?

Hi all,

I am struggling with this problem for a day and cannot find a solution anywhere online. I have four cell arrays with data per country on which I perform operations to find a number of countries that I want to analyse. I have saved these countries in a 27x1 cell array with nonnumerical attributes whose output looks like:

'Belgium'
'Bulgaria'
'Croatia'
'Cyprus'
'Czechia'
'Denmark'
'Estonia'

This is an example of the rows that I want to subtract from other cell arrays with data per country. The problem is that cell arrays do not allow indexing which means that I cannot use these to subtract data from other cell arrays.

What I have tried:

• I have tried str2double to create rows that allow indexing. This resulted in NaN values which did not allow any operation
• I have tried cell2mat which gave the error: Dimensions of arrays being concatenated are not consistent.
• I have tried to create a table from cell arrays, but I couldent paste all the data in it from the different cell arrays because I couldent subtract it

Could anyone help me find a way in which I can use the selection cell arrays as indexing to subtract data from other cell arrays?

Which method would be appropriate?

I have appended the .m file and the arrays to this question. Thank you a lot for considering to provide me guidance in this problem!

Answer 1

[Sammit Jain]

Hi Wouter,

From what I can gather based on your query, you intend to remove ("subtract"?) certain rows from your data, based on a list of countries. So for example, you would like to eliminate the data in the cell array that corresponds to 'Belgium' because it appears on your list.

There doesn't appear to be a direct way to do this. However, you may write a small script to automate this. You may want to work with tables and categorical variables for this one, as they are easier to manage, especially for the operations you're looking to accomplish.

1. Tables: https://www.mathworks.com/help/matlab/ref/table.html
2. Categorical Variables: https://www.mathworks.com/help/matlab/categorical-arrays.html

As a simple fix, you may loop through your list of countries (possibly using a for loop) and then use the method described here to find matches (https://www.mathworks.com/matlabcentral/answers/386171-match-a-categorical-array-in-a-loop). Once a match is found, you can remove the rows from the cell arrays.