CODEWITHSUNDEEP
matlab
AnnaSchumann
AnnaSchumann

Reputation: 1271

Properly set textscan returns empty cell array

I have a .txt file in the format of:

123123  4
123234  4
515511  4
157888  4
854634  4
345661  4

I want to be able to import each column into a different variable. I've tried:

data = textscan(fid, '%f %*[^\n]','HeaderLines',0);   
test = textscan(fid, '%*f %f %*[^\n]','HeaderLines',0);

Which successfully imports the first column of numbers however test returns [].

What is causing this?

Upvotes: 1

Views: 2753

Answers (1)

Robert Seifert
Robert Seifert

Reputation: 25232

At the moment you're scanning the whole file two times - that's not a good idea.

So how about importing everything in one variable and splitting it up afterwards?

DATA = importdata('myFile.txt',' ',0)

data = DATA(:,1);
test = DATA(:,2);

clear DATA

Be aware that if you have headerlines, the code varies a little:

headerlines = 5
DATA = importdata('myData.txt',' ',headerlines)

data = DATA.data(:,1);
test = DATA.data(:,2);

If the white space delimiter ' ' is not working, try tabulator '/t'.

The reason why your approach is not working is the file-ID fid. Imagine fid is a pack of tasty cheese. Every line of the file which got read by textscan is like you have eaten one slice of cheese. So after your command:

data = textscan(fid, '%f %*[^\n]','HeaderLines',0);

there is no cheese left. And your second textscan call is left without any cheese. To make it work you would need to open another similar pack of cheese:

fid = fopen('myData.txt');
data = textscan(fid, '%f %*f %*[^\n]','HeaderLines',0);   
fclose(fid)

fid = fopen('myData.txt');
test = textscan(fid, '%*f %f %*[^\n]','HeaderLines',0);
fclose(fid)

But I tell you, you will get fat. But if you really want to eat cheese, do it as follows:

fid = fopen('myData.txt');
DATA = textscan(fid, '%f %f %*[^\n]','HeaderLines',0);   
fclose(fid)

data = DATA(1);
test = DATA(2);

Upvotes: 3

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