How to delete 'NA' columns from a text file?

1 view (last 30 days)
Hi guys, I have a text file which has 7 rows and 499 columns and in some columns, there are 'NA'
How can i delete them?
Example.txt:
NA T2b t1c t3b
60 79 78 50
7 7 9 7
t2c t3a t2c t3b
4 5 3 NA
0.1 0.1 0.18 0.1
4 4 5 3
  2 Comments
Akira Agata
Akira Agata on 3 Apr 2018
You mean, you want to replace 'NA' with some value, such as 0? or you want to delete row or column with 'NA'?
chocho
chocho on 3 Apr 2018
I want to delete the whole columns which contain 'NA' like in the attached example column 1 and 4 should be deleted completely

Sign in to comment.

Accepted Answer

Stephen23
Stephen23 on 3 Apr 2018
Edited: Stephen23 on 3 Apr 2018
This is easy with textscan, strcmp, and some indexing:
opt = {'MultipleDelimsAsOne',true};
fmt = repmat('%s',1,4); % define how many columns!
[fid,msg] = fopen('test.txt','rt');
assert(fid>=3,msg)
C = textscan(fid,fmt,opt{:});
fclose(fid);
C = [C{:}];
idx = any(strcmp(C,'NA'),1);
D = C(:,~idx);
which generates this matrix:
D =
T2b t1c
79 78
7 9
t3a t2c
5 3
0.1 0.18
4 5
The test file is attached to this answer. It is also easy to write this to a new file:
tmp = D';
len = max(cellfun('length',D(:)));
fmt = sprintf('%%-%ds',len+1);
fmt = [repmat(fmt,1,size(D,2)),'\n'];
[fid,msg] = fopen('test_new.txt','wt');
assert(fid>=3,msg)
fprintf(fid,fmt,tmp{:});
fclose(fid);
this generates a new file which looks like this:
T2b t1c
79 78
7 9
t3a t2c
5 3
0.1 0.18
4 5

More Answers (1)

KSSV
KSSV on 3 Apr 2018
fid = fopen('data.txt','rt') ;
S = textscan(fid,'%s','delimiter','\n') ;
fclose(fid) ;
S = S{1} ;
idx = strfind(S, 'NA');
idx = find((cellfun('isempty', idx)));
S = S(idx)
  1 Comment
chocho
chocho on 3 Apr 2018
@KSSV, I have tried your code, it deleted the rows but I want to delete the columns that have NA and not the rows

Sign in to comment.

Categories

Find more on Text Data Preparation in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!