How to import txt.-files with different columns and numbers/letters?

I want to import two different txt.-files, one with 7 columns and the other one with 9, both have around 1.500.000 rows.

One looks like this:

C:\Bose\....

"Points","Elapsed Time ","Scan Time ","Disp  ","Load 3","T1_Control","T2_Chamber",  
"      ","Sec          ","Sec       ","mm    ","N     ","C         ","C         ",  
     1,        0.00000,     0.00000,  -3.276,   1.658,       -40.0,       -41.5,
     2,        0.00060,     0.00060,  -3.272,   1.711,       -40.0,       -41.5,

Sometimes instead of numbers there are xxxx in some rows.

I tried to import it with:

    [filename, path] = uigetfile({'*.txt'});
    selectedfile = fullfile(path,filename);
    [a] = importdata(selectedfile,',');

It works as long as there are just numbers, but when there are xxxx in a row, the file is just imported to this row and the rest of the file is ignored.

How do I continue the import if there are xxxx in some rows?

Answer 1

[Akira Agata]

If your data file looks like this:

C:\Bose\....
"Points","Elapsed Time ","Scan Time ","Disp  ","Load 3","T1_Control","T2_Chamber",  
"      ","Sec          ","Sec       ","mm    ","N     ","C         ","C         ",  
   1,        0.00000,     0.00000,  -3.276,   1.658,       -40.0,       -41.5,
   2,        0.00060,     0.00060,  -3.272,   1.711,       -40.0,       -41.5,
   3,        0.00060,     0.00060,  -3.272,   1.711,       xxxx,       -41.5,
   4,        0.00060,     0.00060,  -3.272,   1.711,       -40.0,       -41.5,

The following code can read them and convert exceptional characters (like 'xxxx') with NaN.

d = readtable(yourFile,'HeaderLines',3,'ReadVariableNames',false,'Format','%s%s%s%s%s%s%s');
d = varfun(@str2double,d);

The result looks like:

>> d
d =
4×7 table
  str2double_Var1    str2double_Var2    str2double_Var3    str2double_Var4    str2double_Var5    str2double_Var6    str2double_Var7
  _______________    _______________    _______________    _______________    _______________    _______________    _______________
         1                    0                  0             -3.276              1.658               -40               -41.5     
         2               0.0006             0.0006             -3.272              1.711               -40               -41.5     
         3               0.0006             0.0006             -3.272              1.711               NaN               -41.5     
         4               0.0006             0.0006             -3.272              1.711               -40               -41.5

[Eric Helfer]

Thanks for your answer! It works with readtable

Answer 2

[Sven]

Try using readtable() instead. This will import all your data, but changes all data to character vectors. If you want to further use the data, you need to convert the table into a normal array, or cell array in this case, with table2array().

   [filename, path] = uigetfile({'*.txt'});
   selectedfile = fullfile(path,filename);
   A = readtable(selectedfile,'Delimiter',',','ReadVariableNames',false);
   B = table2array(A);

If you need an array you have to use a loop to move each element into a normal array. The table2array() function should actually convert it directly into an array, but it doesn't seem to work, so table2array() and table2cell() both convert it into a cell array.

This is based on my experience, so it might not be the most effective way.

[Eric Helfer]

Thanks for your answer!

readtable helped