Matlab Fgetl Invalid File Identifier
High-Level ASCII ReadThe function load can be used to read ASCII files, provided that the files contain only numbers and the number of columns is fixed.1.1. Example: Read result of the save CommandExecuting the commands% Create a 5x5 arraryM = rand(5);% Create an ASCII file containing the contents of Msave -ascii file.txt M% Read the file using the load commandload file.txt% Should see a variable named file that has the same size as M.whosresults in the contents of file5.txt being imported into a variable named file. To compare M and file5, enterM - fileon the command line.1.2. Example: Read result of save -doubleExecuting the commandsM = rand(5);save -ascii -double file.txt Mload file.txtwhosresults in the contents of file.txt being imported into a variable named file. To compare M and file5, enterM - fileon the command line.1.3. Example: Sunspot Number FilesReading an ASCII-encoded file using load is not always as easy as in the example above. As an example of a the typical effort to read a file, consider the daily total sunspot number data at, which at the time of this writing had two options for downloading ASCII files which were copied here: and.Save to the same directory that is listed when you type pwd (this prints the working directory) on the MATLAB command line.
View it in a text editor (e.g., gedit on Linux, Notepad on Windows, and TextEdit on Mac) and then tryload dayssn.datYou should get an error:Number of columns on line 71678 of ASCII file dayssn.datmust be the same as previous lines.In general, MATLAB's load command is best at reading an ASCII file that contains only numbers (e.g., 1.0, 1e+10, etc.), with a fixed number of columns.The second option for a file was for. Save it to the same directory that is listed when you type pwd. Attemptingload dayssnv0.datgives the same error:Number of columns on line 71678 of ASCII file /home/weigel/dayssnv0.datmust be the same as previous lines.At this point, it makes sense to have a look at the line described in the error. Inspection of line 71678 shows that the problem is that the number of columns changed from three to four at that line. MATLAB's load command attempts to map the file contents to a matrix and the number of columns in the matrix changed, so it gave up.The easy way to resolve this is to open the file with a text editor. Doing this, you will see that at this line there was a new column containing. Remove any lines that contain a.
and then save the file as dayssnv0modified.dat and try to load the file again. Save the removed lines in dayssnv0cut.dat.load dayssnv0modified.datYou should not get an error. MATLAB has loaded the data into an array named dayssnv0modified, which can be verified by typing whos on the command line:dayssnv0modified 71678x3 1720272 doubleThe above is a typical approach new users use for reading an ASCII-encoded file into MATLAB.
Sometimes the file will load without modification. Most of the time, you will need to use a procedure similar to the above, a GUI, or write a program that uses a low-level function such as fprintf.Notes:The data file could have been loading using the GUI found by selected File Import. Doing this with MATLAB 2009a lead to an import without an error message, but the user was not warned that the lines with a.
Matlab Fgetl Invalid File Identifier Matlab
were not loaded. This is not a good practice with respect to GUI design.In practice one would use load for the two files, dayssnv0modified and dayssnv0cut, and then combine the results.To use a different name for the variable, useM = load('dayssnv0modified.dat');% Import data into variable named M.To save the file to a different location than given by MATLAB's pwd command, includ the path in the load command argument, e.g.,M = load('/home/rweigel/Downloads/dayssnv0.dat');An alternative method for doing the above is described in.2.
Low-Level ASCII ReadOne of the most straightforward methods to read an ASCII file is using fgetl. The drawback is that this method is usually slower than using functions such as fscanf. The reason is that fgetl reads a line from a file as a string and then parts or all of the string must be converted to numeric values and placed in a matrix. In contrast, when using fscanf, the structure of the line is pre-specified and so conversion is performed at a lower level using libraries that execute faster. More importantly, fscanf can be used to read an entire file without a loop (and loops can be very slow in scripting languages such as MATLAB).2.1.
Matlab Fgetl Invalid File Identifier Code
FgetlThe help page reads:FGETL Read line from file, discard newline character.TLINE = FGETL(FID) returns the next line of a file associated with fileidentifier FID as a MATLAB string. The line terminator is NOTincluded. Use FGETS to get the next line with the line terminatorINCLUDED. If just an end-of-file is encountered, -1 is returned.2.1.1. Fgetl Examples 2.1.1.1.
Example: Using str2numA file data.txt contains1 19.1 13e42 20.2 15e4The following program reads each line of the file into a string variable named tline:clear;fid = fopen('data.txt','r');while 1tline = fgetl(fid);if ischar(tline)break;endtlineendfclose(fid);The linesif ischar(tline)break;endterminate execution of the while loop if the line does not contain a character (this happens at the end of the file). We want to convert the string into numeric values that can be added, plotted, etc. To do this, use the function str2num, which converts a string to an array provided that the string looks like it contains only numbers.clear;fid = fopen('data.txt','r');while 1tline = fgetl(fid);if ischar(tline),break,endstr2num(tline)endfclose(fid)The final step is to build an matrix, with one line per row of the matrix:clear;fid = fopen('data.txt','r');k = 1;while 1tline = fgetl(fid);if ischar(tline),break,endA(k,:) = str2num(tline);k = k+1;endfclose(fid);2.1.1.2. Example: Using str2numIn the previous example all of lines in the file contained numbers that we wanted to put into a matrix, and these lines could be converted to a numeric array using str2num. Consider a file named data2.txt containing:# A header# A header1 19.1 13e42 20.2 15e4In this case, we need to skip the first two lines.
We can do that by reading them and then doing nothing with the result:clear;fid = fopen('data2.txt','r');% Read first two linesfor i = 1:2tline = fgetl(fid);end% Read lines with numbersk = 1;while 1tline = fgetl(fid);if ischar(tline),break,endA(k,:) = str2num(tline);k = k+1;endfclose(fid);A2.1.1.3. Example: Using regexprepIn the previous example, each line with numbers could be converted using str2num. Consider the file data3.txt:# A header# A header2014-01-01 00:00 19.1 13e42014-01-01 00:01 20.2 15e4The line 2014-01-01 00:00 19.1 13e4 can not be converted properly using str2num.
To see this, enterformat longstr2num('2014-01-01 00:00 19.1 13e4')which displaysans =1.0e+05.0.00000 0 0.00000 1.00000The first value is 2012, so MATLAB has assumed 2014-01-01 meant subtraction. We need to replace these non-numeric characters with a space.
HiThe function if a very slow when comma decimal separator is used. I changed the lines 439 to 454 for:% create a format string for reading data as stringsfs = '%s'; for i=2:numdatacols, fs = fs '%s'; end%#ok% add one more column for the comment fieldfs = fs '%s';% Read columns as stringsrawdata = textscan(fid,fs,'delimiter',textdelimiter);% Convert ',' decimal separator to '.' Decimal separatorrawdata = cellfun(@(x) strrep(x,',','.' ), rawdata, 'UniformOutput', false);% Transform strings back to numbersrawdata = cellfun(@(x) str2double(x), rawdata, 'UniformOutput', false);Now, the function load the lvm file in less than 10 seconds instead of 180 seconds. Maybe you could introduce this modification.Disclaimer: I only test the new code with a file of 8,8 MB with only one segment.
Two bugs in the code that prevent it from working(possibly more) with some lvm files.one is mulitple tabs. Changed line 178 tovin = textscan(linein,'%.s%s','delimiter','t','whitespace',','MultipleDelimsAsOne', 1);second is muliple lines: there is a check at line 237 for a single extra line but it should be more general skipping over all extra blank lines-for example, in my lvm the data had two tab's and two extra blank lines after the first header.while (isempty(linein))if (feof(fid)), return; end;linein=fgetl(fid);end.
2 Oct 20173.12.0.0Fixed bug that prevented importing 'data-only'.lvm files.8 Apr 20173.1.0.0add graphic8 Apr 20173.1.0.0v3.1 - More robust handling of files with missing data points.