Why importdata can only import a few lines of a .txt file?

Hello everyone,

I am using importdata to import data from a .txt file:

filename    = '123.txt';
data        = importdata(filename);
data        = data.data;

• The .txt file is as attached. I used Excel to check the .txt file and it shows 24755 lines of data in addition to 1 line of header text.
• However, importdata can only import the first 66 lines.
• I also tried to use the "Import Data" button on the MATLAB panel and it worked fine. Nevertheless, I need to process a large number of .txt files and I certainly need to use code instead of clicking the "Import Data" button for hundreds of times.

It seems something wrong when using this importdata function, but I could not find out why up to now. Can anyone help me figure it out?

Thanks!

Sincerely,

Junfei Tang

Answer 1

[Walter Roberson]

importdata() cannot handle 1.#QNAN0e+000 .

filename    = '123.txt';
opt = detectImportOptions(filename);

The above only needs to be done once for each group of files that have the same headers. After that you can loop over the files,

data = readtable(filename, opt);

This will give you a table() object that has, for example,

            time            V_Inverter_Phase_A_Inverter_Phase_B_    V_Rectifier_Phase_A_Rectifier_Phase_B_    V_Rectifier_Positive_Rectifier_Negative_    I_L_exc_    I_R_tr_1_    I_R_tr_2_
    ____________________    ____________________________________    ______________________________________    ________________________________________    ________    _________    _________
    1.39487416755957e-09                  48.60414                                0.01123047                                 -1.181915                    2.381693    -2.161491    0.5377774
    1.39488942618726e-09                  48.60414                                0.01122113                                 -1.181929                    2.381693     -2.16149    0.5379625
    1.39489002293214e-09                  48.60414                                0.01147461                                 -1.181885                    2.381693     -2.16149    0.5383048
    2.39489002240578e-09                  48.66073                                0.01171875                                 -1.181641                    2.381693    -2.111191    0.5515398
    2.51989002580944e-09                  48.66698                                0.01171875                                 -1.181641                    2.381693    -2.104903    0.5532185
    2.76989002567785e-09                  48.67606                                0.01171875                                 -1.181641                    2.381693    -2.092325    0.5566501
    3.26989002541467e-09                    48.686                                0.01184082                                 -1.181641                         NaN    -2.067164    0.5635144
    4.15460238434306e-09                  48.69257                                0.01226807                                 -1.181824                         NaN     -2.02264    0.5756616
    4.27171845118757e-09                   48.6927                                 0.0123291                                 -1.181885                    2.381692    -2.016746    0.5772697

You can refer to individual columns. Or if you want all of the columns together as a numeric array, then it would be

   data{:,:}

[Junfei Tang]

It works. Thank you very much! :-)