Reading a binary data file
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Hello,
I am trying to import and read a binary data file of the following format in MATLAB. I need to read in all the data, however at this point im just trying to read in the first 4 char, but i keep getting a blank array. Nothing seems to be working and I have been stuck for days.
Thanks in advance for your help!
fid = fopen('file.dat','r');
if fid <0
error('error opening file %s\n file.dat')
end
Program_label = fread(fid,[1 4],*char)
fclose(fid);
m = memmapfile('GSS1_t023_is_phcorr_ideal.dat');
m.Format
回答（1 个）
Jan
2019-6-7
fid = fopen('file.dat','r');
if fid <0
error('error opening file %s\n file.dat')
end
Program_label = fread(fid, [1 4], '*char'); % With quotes
Program_version = fread(fid, 1, 'single');
Type_label = fread(fid, [1 4], '*char');
nCols = fread(fid, 1, 'uint32');
nRows = fread(fid, 1, 'uint32');
...
fclose(fid);
8 个评论
KatherineS
2019-6-8
Please explain exactly, what you are doing. How do you obatin the "[]"? "The output for the values shows..." is not clear enough to understand this. Program_label is read as char vector, such that it is unlikely, that the empty matrix [] is shown anywhere. Therefore I assume, that your method to display the contents of the variables is flawed, or that the file really contains '[] ' as first 4 characters.
KatherineS
2019-6-8
Running the code you provided on the file, I obtain what is shown in the image in my workspace. the first characters in the file should be imageLayerStack (abcdef1 v 1.14) 
Walter Roberson
2019-6-8
Please show us
double(Program_label)
I suspect that it contains unprintable characters, such as binary 0.
the first characters in the file should be imageLayerStack (abcdef1 v 1.14)
That disagrees with the layout you provided, which says that there should be 4 characters followed by a single precision float
Jan
2019-6-8
Show us:
fid = fopen('file.dat','r');
if fid <0
error('error opening file %s\n file.dat')
end
data = fread(fid, [1 16], '*uint8')
fclose(fid)
KatherineS
2019-6-8
Hello,
The data variable shows as (in image) and double(Program_label) shows as []
Thank you all very much for your help in this.
Walter Roberson
2019-6-8
The file is empty.
Walter Roberson
2019-6-8
dinfo = dir('file.dat')
and look at the bytes information. I think it will show 0
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