CODEWITHSUNDEEP
matlabtext-filestextscan
Eghbal
Eghbal

Reputation: 3783

How read this structure using MATLAB textscan function?

I have this structure in a text file named my_file.txt.

# Codelength = 3.74556 bits.
1:1:1:1 0.000218593 "v12978"
1:1:1:2 0.000153576 "v1666"
1:1:1:3 0.000149092 "v45"
1:1:1:4 0.000100329 "v4618"
1:1:1:5 5.1005e-005 "v5593"
1:1:1:6 3.53112e-005 "v10214"
1:1:1:7 3.36297e-005 "v10389"
1:1:1:8 2.85852e-005 "v2273"
1:1:1:9 2.63433e-005 "v13253"
1:1:1:10 2.41013e-005 "v10109"
1:1:1:11 2.01778e-005 "v9204"
1:1:1:12 1.73753e-005 "v16508"
1:1:1:13 1.34519e-005 "v335"

This is a small part of this text file. Main file has more than 600,000 lines. I want have a array with this properties:

First column : 1 1 1 1 1 1 1 ... (left values in txt file)
Second column : 1 1 1 1 1 1 1 ...
Third column : 1 1 1 1 1 1 1 ...
Fourth column : 1 2 3 4 5 6 ...
Fifth column : 0.000218593 0.000153576 000149092 000100329 ....

and a string containing last right text file items ("v12978", "v1666" ...). How can I do this in MATLAB?

Upvotes: 0

Views: 178

Answers (1)

Rody Oldenhuis
Rody Oldenhuis

Reputation: 38032

Suppose that textfile.txt is your data file, then

fid = fopen('textfile.txt', 'r');
oC = onCleanup(@() any(fopen('all')==fid) && fclose(fid) );

data = textscan(fid,...
                '%d:%d:%d:%d %f %q',...
                'Headerlines', 1);

fclose(fid);

will give 

data = 
    [13x1 int32]    [13x1 int32]    [13x1 int32]    [13x1 int32]    [13x1 double]    {13x1 cell}

That already fits your description of the desired output format.

Now, you could go on and concatenate the numbers into a single array, where you should take care of the fact that MATLAB downcasts by default: 

numbers = cellfun(@double, data(1:end-1), 'UniformOutput', false);            
numbers = [numbers{:}];

but well, that all depends on your specific use case.

You might want to split the reading/processing up in chunks of say, 10,000 lines, because reading 600k lines all at once can eat away your RAM. Read the documentation on textscan how to do this.

Upvotes: 1

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