How do I read a file in using fopen correctly

I am trying to read in spectroscopic data in using fopen and place the data into the y array. The file dimensions are 69 * 22533. What am I doing incorrectly?

x = 1:5; %5
y = zeros(69,22533);
fileID = fopen('Pandora166s1_LabGSFC_20200115_L0_subset (1).txt','w');
fprintf(fileID,'%d %4.4f\n',y);
fclose(fileID);

[Walter Roberson]

That is code to write a lot of zeroes into a file, not to read from a file.

Your format hints that in your file the first column is an integer. Is that some kind of index? If so then how does it relate to the location to place the data into y?

[Daniel Montgomery]

It is an index less text file. My first character is a string I want to import the data from matlab. The data in Y would start at zero and start a new row at the 69th character.

[Walter Roberson]

Please show an extract of the file.

Answer 1

[Daniel Montgomery]

I did not know a consistent number of characters was required for reading in a file. What would be the best way to to import this to get cell seperated values? I am trying to isolate a range of cloumns for data analaysis.

[Walter Roberson]

Consistency of line length is not usually required, but when we asked about the format you said "The data in Y would start at zero and start a new row at the 69th character". That would not make sense unless you had a fixed width line.

[Walter Roberson]

What you attached has three columns per line, such as "Instrument", "type:" and "Pandora". But that looks pretty accidental to me and it looks more likely that you have a parameter name phrase followed by : then a parameter value that is not necessarily numeric. Because it is not numeric we have to guess that in non-numeric cases you want until the end of the line. The example you give only shows one numeric value on any line but we can speculate that there might be lines with multiple numbers.

Answer 2

[Daniel Montgomery]

Instrument type: Pandora

Instrument number: 166

Spectrometer number: 1

[Walter Roberson]

That is not a consistent number of characters per row?

What would you expect the output to be for that extract?