How can I create a new column counting the number of rows of a table?

I have a 100x2 table, named t. I would like to add a third column which simply count the number of items of the table - that is an Index which I can print with the other columns. The original table looks like this:

To add an indexing column in R I would probably do a very simple operation like this: df$index <- 1:nrow(df).

What is the easiest solution in Matlab? Actually I am able to obtain what I want (see image below), but the code I use is really horrible...

%create new empty index column, the same size as table t
t.index=zeros(size(t, 1), 1)
%change column order, so that t is the first column
t = t(:,[3 1:2]);
%number index column
x=[]
index=0
for i=1:size(t, 1) 
  index=index+1
  x(end+1) = index
end
t.index=x'

[Birdman]

What does number of rows have to do with creating a new column?

[Emanuele Cappella]

You're right, I did not explain myself well enough. Please see the edited question, which I hope is clearer

Answer 1

[Steven Lord]

The command you need is very similar to the R command you posted.

% Build a sample table
t = table(["call"; "free"; "txt"; "text"; "mobil"; "claim"], randi(100, 6, 1), ...
          'VariableNames', {'Word', 'Count'})

% Add a new variable to the table.
% Use the height function to ensure it's the correct height
t.index = (1:height(t)).'

% If you want the index variable to be displayed first,
% reorder the columns using indexing
t = t(:, [3 1 2])

Answer 2

[KL]

In MATLAB indexing is inherent, be it array or tables. If you have a table like,

dummy = {'call',366;'free',216;'txt',163};
t = cell2table(dummy,'v',{'words','count'})

t = 

      words     count
      ______    _____

      'call'    366  
      'free'    216  
      'txt'     163

there are number of ways you can access the content of it. This is well explained in the documentation,

https://www.mathworks.com/help/matlab/matlab_prog/access-data-in-a-table.html

To simplify,

--> to access a column, you can either use.

>> t.words

ans = 

      'call'
      'free'
      'txt'

or

>> t{:,1}

ans = 

      'call'
      'free'
      'txt'

--> just to access specific row of that column,

>> t.words(1)

ans = 

      'call'

or

>> t{1,1}

ans = 

      'call'

As you can see, creating a new column called index is completely redundant.