Thread Subject:

separating dataset in one file

If the file contains this format:

2.4
4.5
6.7
8.9
S
3.3
2.22
3.43
5.64

I need to make two data sets how do i read such a way that i can stop reading at S and start reading next data set.

                         

On May 24, 9:29 am, "nman2084 " <ng2...@yahoo.com> wrote:
> If the file contains this format:
>
> 2.4
> 4.5
> 6.7
> 8.9
> S
> 3.3
> 2.22
> 3.43
> 5.64
>
> I need to make two data sets how do i read such a way that i can stop reading at S and start reading next data set.

Probably the quickest way is to read the entire file in as string data
using textscan, then look through the cell array for the line starting
'S' using strmatch. Once you've found it, you can split the cell array
in two and convert to numeric data.
Have a go at coding this and we'll help debug it.

Thanks,
 I am facing problem with that S how do i stop reading until 'S'.

fid = fopen('testDat.txt');

k = 0;
while ~feof(fid)
    curr = textscan(fid,'%4f');
end
    
fclose(fid);

On 5/23/2011 4:29 PM, nman2084 wrote:
> 2.4
> 4.5
> 6.7
> 8.9
> S
> 3.3
> 2.22
> 3.43
> 5.64

Do you know the number of entries a priori?

--

On 5/23/2011 4:29 PM, nman2084 wrote:
> If the file contains this format:
>
> 2.4
> 4.5
> 6.7
> 8.9
> S
> 3.3
> 2.22
> 3.43
> 5.64
>
> I need to make two data sets how do i read such a way that i can stop
> reading at S and start reading next data set.

Oh, another idea struck...

If it's always a single character, make use of the fact that Matlab will
barf silently on the bad conversion...if it's not a fixed length string,
then Tideman's answer...

 >> fid=fopen('test.dat','rt');
 >> x=fscanf(fid,'%f')
x =
     2.4000
     4.5000
     6.7000
     8.9000
 >> fseek(fid,2,0); % NB 2 bytes for \n on Windows -- the 'S' was eaten
 >> y=fscanf(fid,'%f')
y =
     3.3000
     2.2200
     3.4300
     5.6400
 >> fid=fclose(fid);
 >> type 'test.dat'
2.4
4.5
6.7
8.9
S
3.3
2.22
3.43
5.64

>>

On 5/23/2011 7:11 PM, dpb wrote:
...

> Oh, another idea struck...
>
> If it's always a single character, make use of the fact that Matlab will
> barf silently on the bad conversion...if it's not a fixed length string,
> then Tideman's answer...

Got to thinking as hit the "send" button...there's a cleaner way as the
file pointer didn't actually move when the conversion failed...

 >> x=fscanf(fid,'%f')
x =
     2.4000
     4.5000
     6.7000
     8.9000
 >> fgetl(fid)
ans =
S
 >> y=fscanf(fid,'%f')
y =
     3.3000
     2.2200
     3.4300
     5.6400
 >> fid=fclose(fid);
 >>

This way as long as it's a single line of text you should be golden.

--

On May 24, 12:16 pm, dpb <n...@non.net> wrote:
> On 5/23/2011 7:11 PM, dpb wrote:
> ...
>
> > Oh, another idea struck...
>
> > If it's always a single character, make use of the fact that Matlab will
> > barf silently on the bad conversion...if it's not a fixed length string,
> > then Tideman's answer...
>
> Got to thinking as hit the "send" button...there's a cleaner way as the
> file pointer didn't actually move when the conversion failed...
>
>  >> x=fscanf(fid,'%f')
> x =
>      2.4000
>      4.5000
>      6.7000
>      8.9000
>  >> fgetl(fid)
> ans =
> S
>  >> y=fscanf(fid,'%f')
> y =
>      3.3000
>      2.2200
>      3.4300
>      5.6400
>  >> fid=fclose(fid);
>  >>
>
> This way as long as it's a single line of text you should be golden.
>
> --

Here's my method:
fid=fopen('test.txt','rt');
c=textscan(fid,'%s');
fclose(fid);
indx=strmatch('S',c{1})
a=str2num(char(c{1}(1:indx-1)));
b=str2num(char(c{1}(indx+1:end)));

On 5/23/2011 8:05 PM, TideMan wrote:
> On May 24, 12:16 pm, dpb<n...@non.net> wrote:
>> On 5/23/2011 7:11 PM, dpb wrote:
>> ...
...
>>> Oh, another idea struck...
...
>> Got to thinking as hit the "send" button...there's a cleaner way ...
>>
>> >> x=fscanf(fid,'%f')
>> >> fgetl(fid)
>> >> y=fscanf(fid,'%f')
>> >> fid=fclose(fid);
...
>
> Here's my method:
> fid=fopen('test.txt','rt');
> c=textscan(fid,'%s');
> fclose(fid);
> indx=strmatch('S',c{1})
> a=str2num(char(c{1}(1:indx-1)));
> b=str2num(char(c{1}(indx+1:end)));

Yeah, that, too... :)

If OP needs to actually verify it is an 'S' in the file, yours does
specifically--I just assumed some text although easy enough to test what
the fgetl() line returns.

Guess OP can choose... :)

--