How to read and take a part of data of a text file in MATLAB?

1 view (last 30 days)
Dear everyone,
Please help me to solve this problem. I need to make a code that can read data from a text file. The format of the file is as follows:
0.1 ABC63-820
0.2 S815
...
1.0 EG813
I want to take out three arrays.
One is the first column: X=[0.1 0.2 ... 1.0].
Another one is the last two digits of the second column: Y=[20 15 ... 13].
The last one is the rest of the second column: Z=[ABC63-8 S8 ... EG8].
Can anyone help me to write a code to take out these data?
Thank you so much!

Accepted Answer

dpb
dpb on 21 Aug 2014
Edited: dpb on 21 Aug 2014
For a file with your three rows above...
>> fid=fopen('phan.dat');
>> c=textscan(fid,'%f %s','delimiter',' ')
c =
[3x1 double] {3x1 cell}
>> d=cell2mat(c(:,1));
>> for i=1:length(c{2})
s=deblank(char(c{2}(i)));
d(i,2)=str2num(s(end-1:end));
ss(i,1)={s(1:end-2)};
end
>> d
d =
0.1000 20.0000
0.2000 15.0000
1.0000 13.0000
>> ss
ss =
'ABC63-8'
'S8'
'EG8'
>>
Couldn't think of a neater way to get the two end characters of a variable-length cellstr...can't do triple-level indexing so did the conversion to character string and deblank to be able to get the two end character positions.
Preallocate first for real file, of course...
ADDENDUM
I figured out where I fouled up the anonymous function to convert the last two digits and get the strings via cellfun
y=cell2mat(cellfun(@(x) str2num(x(end-1:end)),c{2},'uniform',0));
z=cellfun(@(x) x(1:end-2),c{2},'uniform',0);
with the original request for different arrays for the three results.
How overall time will compare w/ two scannings via cellfun vis a vis one loop for larger files I don't know and didn't test.

More Answers (0)

Categories

Find more on Data Import and Export 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!