How to create a table in MATLAB?

Question

I’m doing a job I want to create the following table:

I have tried several commands like table and readtable and always returns me the following message :

Undefined function 'readtable' for input arguments of type 'char'. 
 Undefined function 'table' for input arguments of type 'char'.

I also tried to import from excel and it didn’t work. I know it’s simple, but I’m not getting it.

Answer 1

If you already have the table in Excel, the way it might be easier is to export the Excel data to a file CSV (Comma-Separated Value). Just go on the menu "Filing cabinet" and choose the option "Save as". In the dialog window, choose the file type as CSV:

My Excel is in Portuguese, which is why it uses the semicolon (;) in place of the comma (,) as separator, since the comma in Portuguese is used to separate the decimals into numbers (the point is used to separate decimals in English, so there is no confusion in reading the file). The CSV file, for me, kept this content:

Componente;Amostra MT(phr);Amostra LN (phr)
Elastrômetro;100;100
Cargas;110;60
Plastificante;34;9
Ativador de vulcanização;4,5;4,5
Auxiliar de fluxo e processo;4,5;4,5
Agente acelerador de vuncanização;5,5;6

Once you have this file, you can import the data to an array in MATLAB using the following code:

arquivo = fopen('c:\temp\teste.csv', 'r');
dados = textscan(arquivo,'%s%s%s','delimiter',';')
fclose(arquivo);

What this code does is (1) open the file for reading, (2) read the data according to the specified formats and delimiter, and (3) close the file. Note that I forced the delimiter as semicolon, because of the file exported by my Excel. You may not need to do the same if your Excel is in English and export separating the data with comma. Also note that I am formatting everything as a string (using %s for all columns). The ideal would be to import the numerical values and convert them appropriately to float, but you can do this later (or edit the file to manually remove the header row if this data is not important).

The result is a matrix with the following columns and rows:

>> dados

dados = 

    {7x1 cell}    {7x1 cell}    {7x1 cell}

And you can access the values using the following syntax to get the columns individually:

>> dados{1}

ans = 

    'Componente'
    'Elastrômetro'
    'Cargas'
    'Plastificante'
    'Ativador de vulcanização'
    'Auxiliar de fluxo e processo'
    'Agente acelerador de vuncanização'

>> dados{2}

ans = 

    'Amostra MT(phr)'
    '100'
    '110'
    '34'
    '4,5'
    '4,5'
    '5,5'

>> dados{3}

ans = 

    'Amostra LN (phr)'
    '100'
    '60'
    '9'
    '4,5'
    '4,5'
    '6'

P.S.: There is also called function csvread, which also exists in the 2013 version (although the documentation does not make it very clear). She can help you, but is less flexible in reading the files and only reads data numerical (i.e., your file may not have text). Another alternative is the function xslread, already described in this other question.

---

EDITION:

Just to make it more complete, here is a version that converts the numerical data appropriately. Remember that I need to replace the comma by semicolon because my data was exported via an Excel in English. Conversion to number only from the second line (note the index (2:end) used to access the columns) whether to ignore the header and keep it as a string.

The function cellfun which I use is very interesting as it allows use/call another function (in my example, the function str2num) for each value in a matrix.

Here’s the code:

arquivo = fopen('c:\temp\teste.csv', 'r');
dados = textscan(arquivo,'%s%s%s','delimiter',';')
fclose(arquivo);

% Conversões:
% Para cada coluna (2 e 3), primeiro substitui a vírgula (,) por ponto (.)
% e então converte para número apenas os dados da segunda linha em diante
% (note o (2:end) na indexação dos dados).
dados{2}(2:end) = strrep(dados{2}(2:end), ',', '.')
dados{2}(2:end) = cellfun(@str2num, dados{2}(2:end), 'UniformOutput', 0)

dados{3}(2:end) = strrep(dados{3}(2:end), ',', '.')
dados{3}(2:end) = cellfun(@str2num, dados{3}(2:end), 'UniformOutput', 0)

Which now results in values properly converted to numbers within MATLAB:

>> dados{2}

ans = 

    'Amostra MT(phr)'
    [   100]
    [   110]
    [    34]
    [4.5000]
    [4.5000]
    [5.5000]