Question about headerlines commend

Hi, everyone.

this is my code.

This code is originally intended to handle raw data in 14 columns.

I want to process raw data in two columns in this code.

When running this code, the Header = textscan (FID, '%s', HeaderLines); %GetHeader section says, "Invalid file ID. The error occurs with the phrase "Please use fopen to generate a valid file ID."

Which part should I revise?

Note that the data I want to apply to this code is in .str format and consists of two columns in total.

% READ AND PROC DATA
T_ObsTime = [];
T_DMSMixr = [];

a1 = double(input("Enter a slope of STD CAL: "));
b1 = double(input("Enter a Y-intercept of STD CAL: "));

for n = 1:length(DataList)-1
    
    % READ
    HeaderLines = 1; % the number of header lines
    
    FID = fopen([DataFolder,'\',DataList(n)], 'r') ; % Set File ID
   Header = textscan(FID, '%s', HeaderLines); % Get Header
     % Header = textscan(FID, repmat(' %s', 1, 2), HeaderLines); % Get Header  
%     StartTime = datenum([char(Header{1}),' ',char(Header{2})],'mm/dd/yyyy HH:MM:SS');

    T_Raw = textscan(FID, repmat(' %n', 1, 2)); % Get RAW data
    
    fclose(FID);
    
%     PROCESSING
    GetTime = datetime(datevec(datenum(0,0,0,0,0,Tildas_Raw{1})...
        + datenum(1904,1,1,0,0,0) - datenum(0,0,0,9,0,0)));% convert UNIX time to MAT time + UTC (-9 hr)
    
    T_ObsTime = [T_ObsTime; GetTime];
    T_DMSMixr = [T_DMSMixr; ((Tildas_Raw{2}-b1)./a1)]; %cal factor 값 계산..
end

%% GET HOURLY MEAN DMS
% REMOVE OUTLIERS
% T_DMSMixr(TFrm) = NaN;

% SET HOURLY TIME
Get_DateVec = datevec(Tildas_ObsTime);
Get_DateVec(:,5:6) = 0;
SetTime = datevec([datenum(Get_DateVec(1,:)):datenum(0,0,0,1,0,0):datenum(Get_DateVec(end,:))]);

% PROC
for n = 1 : length(SetTime)
    
    i = find(Get_DateVec(:,1) == SetTime(n,1) &...
        Get_DateVec(:,2) == SetTime(n,2) &...
        Get_DateVec(:,3) == SetTime(n,3) &...
        Get_DateVec(:,4) == SetTime(n,4));
    
    Get_1HDMS(n,1) = nanmean(T_DMSMixr(i).*1000,'all');
    
end

[Siddharth Bhutiya]

I see that you are using datenum and datevec and doing manual conversions between different time representations and timezones. This is error prone and your life would be much easier if you do all this in datetime. For example, in the last for loop you seem to be converting datenums to datevecs and comparing individual fields, you could do this in one comparision if you use datetimes.

[Walter Roberson]

use fullfile to construct your file name instead of []

Answer 1

[Voss]

Check why fopen in this line

FID = fopen([DataFolder,'\',DataList(n)], 'r')

returns -1 for FID.

Better yet, use the second output from fopen to have your code tell you what's wrong:

filename = [DataFolder,'\',DataList(n)];
[FID,ERRMSG] = fopen(filename, 'r');
if FID < 0
    error('Error opening "%s":\n%s',filename,ERRMSG)
end

Check that the file name reported is what you expect and that the file exists.

The problem may be that DataList is not what you think it is. What is it?