Read a Special Text File

I was wondering if there is a quick way to read the following text file sample where the first data line starts with a bracket. I would like to avoid the hassle of manually removing the bracket from every file I obtain. I use the following command for now after I remove the bracket.

Thanks.

data = textscan(Fopen, '%d %f %d %d %d;', 'HeaderLines',2)

file.txt

[Stephen23]

A simple and very efficient approach would be to simply define the square bracket as whitespace, which you can do using TEXTSCAN's WHITESPACE option. Another good approach would be to use a fixed-width import via READTABLE.

Using STR2NUM is not very efficient.

Answer 1

[Stephen23]

Here are two much more efficient approaches.

The first is exactly like you are doing now, just adding the WHITESPACE option to efficiently ignore the square bracket:

fnm = 'textfile.txt';
fmt = '%d%f%d%d%d;';
opt = {'HeaderLines',2, 'Whitespace',' \t['};
fid = fopen(fnm,'rt');
data = textscan(fid, fmt, opt{:})

data = 1×5 cell array
    {11130×1 int32}    {11130×1 double}    {11130×1 int32}    {11130×1 int32}    {11130×1 int32}

fclose(fid);

The second is to import the file as table, which has headers and may be more convenient to access:

opt = detectImportOptions(fnm, 'FileType','fixedwidth', ...
    'VariableWidths',[6,9,16,16,16], 'VariableNamesLine',1, ...
    'VariableNamingRule','preserve', 'Range',3, 'Whitespace',' [', ...
    'ExtraColumnsRule','ignore');
tbl = readtable(fnm,opt)

tbl = 11130×5 table
    Sample    Time     Commanded Pos    Encoder 1 Pos    Encoder 2 Pos
    ______    _____    _____________    _____________    _____________

       0          0          0                0                0      
       1      0.001          0                0                0      
       2      0.002          0                0                0      
       3      0.003          0                1                0      
       4      0.004          0                4                0      
       5      0.004          0                7                0      
       6      0.005          0               14                0      
       7      0.006          0               20                0      
       8      0.007          0               27                0      
       9      0.008          0               37                0      
      10      0.009          0               47                0      
      11       0.01          0               57                1      
      12      0.011          0               66                3      
      13      0.012          0               76                4      
      14      0.012          0               87                6      
      15      0.013          0               98                7      

[AEW]

Thank you!

Answer 2

[Voss]

% read file into character vector data
data = fileread('textfile.txt');
% remove the first two lines
idx = find(data == newline(),2);
data(1:idx(end)) = [];
% convert to numeric
M = str2num(data);
% show some results
format long
disp(M(1:10,:));

                   0                   0                   0                   0                   0
   1.000000000000000   0.001000000000000                   0                   0                   0
   2.000000000000000   0.002000000000000                   0                   0                   0
   3.000000000000000   0.003000000000000                   0   1.000000000000000                   0
   4.000000000000000   0.004000000000000                   0   4.000000000000000                   0
   5.000000000000000   0.004000000000000                   0   7.000000000000000                   0
   6.000000000000000   0.005000000000000                   0  14.000000000000000                   0
   7.000000000000000   0.006000000000000                   0  20.000000000000000                   0
   8.000000000000000   0.007000000000000                   0  27.000000000000000                   0
   9.000000000000000   0.008000000000000                   0  37.000000000000000                   0

disp(M(end-9:end,:));

   1.0e+05 *

   0.111200000000000   0.000098460000000                   0   1.003280000000000   0.222970000000000
   0.111210000000000   0.000098470000000                   0   1.002280000000000   0.222750000000000
   0.111220000000000   0.000098480000000                   0   1.001270000000000   0.222530000000000
   0.111230000000000   0.000098480000000                   0   1.000280000000000   0.222310000000000
   0.111240000000000   0.000098490000000                   0   0.999280000000000   0.222090000000000
   0.111250000000000   0.000098500000000                   0   0.998290000000000   0.221870000000000
   0.111260000000000   0.000098510000000                   0   0.997310000000000   0.221640000000000
   0.111270000000000   0.000098520000000                   0   0.996330000000000   0.221420000000000
   0.111280000000000   0.000098530000000                   0   0.995360000000000   0.221190000000000
   0.111290000000000   0.000098540000000                   0   0.994390000000000   0.220970000000000

[AEW]

Thank you!

[Voss]

You're welcome!

Answer 3

[David Hill]

r=readmatrix('file.txt');%see if this will work

[AEW]

Thank you for the answer.

Unfortunately, it does not work. I get the following:

[David Hill]

If you attach the text file, I would be able to help better.

[AEW]

Please find it attached.

Thanks.