Import several tables from one txt file in Matlab

Hi All!

I'm trying to read several tables from one text file in Matlab. The format can be a bit adjusted, but the principle of the file structure is this:

#TableID tab01
Length    Width
1         2
3         4

#TableID tab02
Weight    Volume    Density
10        20        0.5
30        40        0.75
50        100       0.5

I tried to follow this article "Import Block of Mixed Data from Text File into Table or Cell Array", but detectImportOptions always thinks it's one table. The DelimitedTextImportOptions object seems to support multiple sections for the DataLines property (see help), but I can't find the way to do it with detectImportOptions.

The long story short: How can I (preferably using detectImportOptions and not writing my own code) import the given text file, detect tables IDs, autodetect variables names for both tables, and get two tables themselves, i.e.

1         2
3         4

and

10        20        0.5
30        40        0.75
50        100       0.5

Thanks a lot in advance!

P.S. This example is no good for me, while a) no auto detection from variables names, b) no auto detection of the matrices separation (look which output he expects).

Answer 1

[Stephen23]

str = fileread('temp.txt');
tkn = regexp(str,'^#TableID[^\n]*\s*([^\n]+)([^#]*)','lineanchors','tokens');
tkn = vertcat(tkn{:});
nml = size(tkn,1);
out = cell(1,nml);
for k = 1:nml
   hdr = regexp(tkn{k,1},'\S+','match');
   mat = sscanf(tkn{k,2},'%f',[numel(hdr),Inf]).';
   out{k} = array2table(mat,'VariableNames',hdr);
end

Checking:

out{1}

ans = 2×2 table
    Length    Width
    ______    _____

      1         2  
      3         4  

out{2}

ans = 3×3 table
    Weight    Volume    Density
    ______    ______    _______

      10        20        0.5  
      30        40       0.75  
      50       100        0.5  

[Alex Kashuba]

It works indeed, thanks. Pity, I hoped it's already implemented in standart import tools.

[Stephen23]

@Alex Kashuba: yes, I also tried using the inbuilt tools. There seems to be no way using the detectImportOptions and readtable process (shown in the link that you gave) to automatically adjust to the number of columns in the block being imported. It is certainly possible to mess around with the options structure and change the number of columns based on the file data somehow, but in the end that required significantly more effort than just importing the entire file and doing a bit of string manipulation.

[Stephen23]

@Tessa van Kol: please upload a sample file by clicking the paperclip button.

What should the TITLE table contain?

[Tessa van Kol]

I posted my question and sample file in here How to overwrite matrix in txt file with another matrix?. Maybe @Stephen23 can help me with that?