In my scenario, I have 100 nodes. Each time a random node out of them generates a data. I wish to record them in previously created files.
I have been using switch-case style to open the particular file associated with a node. However, it's clumsy for 100 nodes already and I need to increase the number of nodes. I was looking for a straight forward manner of opening a file based on node. I found bit hint here:
Stackoverflow_a_year_ago
But I'm unable to pick and open a particular file, say if the random node is 125, I'll open n125.txt file. Any help is appreciated. Here goes the code:
number_of_nodes=100;
for i=1:number_of_nodes
rand_node=ceil(rand(1,1)*100);
rand_output=ceil(rand(1,1)*10);
switch(rand_node)
case{1}
f1=fopen('n1.txt', 'a+');
fprintf(f1, rand_output);
fclose(f1);
case{2}
f2=fopen('n2.txt', 'a+');
fprintf(f2, rand_output);
fclose(f2) ;
end
end
Also, tried,
%..........................................
Names = dir('myprog*.TXT');
Names.name; %returns all file names.
Maybe I'm misunderstanding your question but the answer seems obvious:
fid=fopen(sprintf('n%d.txt',rand_node), 'a+');
fprintf(fid, rand_output);
fclose(fid);
Related
I have a text file (5 columns "\t" separated) that's being written to by another software. I need to take the readings from the file and do some calculations. Is there a was to read the new lines added to the file and process it then repeat again for every new set of lines. I don't mind a bit of delay as long as it does the job.
My idea is to start reading the file line by line until the end of file, then it will read from where it stopped last until the new end of file ...etc.
Can this be done in Matlab? Can I specify the starting line for the file reading? can I also update the end of file point?
To prevent the loop from breaking at the eof point, I think I should set my loop to be controlled by time or anything else, while it should check for eof at the end of every iteration.
I've mostly worked with Matlab, but if there is a better option to use for this purpose (that I can reasonably learn) please feel free to guide me.
Edit1: I've tried using dlmread as you suggested, when I read the file outside the loop it reads the file correctly even when I change R1 and with the other software updating the text. However, when I put it in a loop I get this error:
Error using dlmread (line 143)
Empty format string is not supported at the end of a file.
Here is my code to read it multiple times:
clear all
x=0;
R1=0; C1=0;
while(x<10)
M = dlmread('tst_4.txt','\t',R1,C1);
R1=length(M);
x=x+1;
end
Thanks
You can used dlmread(filename,delimiter,R1,C1). Where R1 and C1 are the row and column offset respectively. By setting the row offset to the last row that you have read, you can read the file content excluding what you would have already read.
Is there any way to create an empty .mat file from a terminal session? Basically, what I am doing is brain graph analysis. The software I am using, if an entire brain is scrubbed (ie, if the displacement of the brain is greater than a certain threshold) the output file will be left out or will be very small. When analyzing, however, I need to be able to eliminate both subjects from the analysis if the entire brain is scrubbed/too much of the brain is scrubbed. To accomplish this, the easiest way would be to simply check the dimensions of the output file within matlab, and if they are below the arbitrary threshold I decide then both subjects will just be skipped over for analysis. The issue is, I can easily check if a file contains too few remaining frames, however, if the resulting file contains no frames, it will entirely just not exist. As the outputs are all sorted, the only thing I need to do is check consecutive files' dimensions, and if one of the files does not contain enough values, then I can simply skip over it entirely. Simply touching a blank file obviously will not work, since it will not contain any encoding. I hope this is a good explanation for my motivation to do this, and if any of you know of any suggestions, please let me know.
A simple solution would be to create an empty file from Matlab and duplicate the file when needed from the console.
Just open Matlab, set to the destination folder and type this:
clear all
save empty.mat
Then, when needed, copy the file from the console. :)
Saving the contents of an empty struct creates an empty .mat file:
emptyStruct = struct;
save('myFile.mat','-struct','emptyStruct');
I am new to MATLAB programming and some of the syntax escapes me. So I need a little help. Plus I need some complex looping ideas.
Here's the breakdown of what I have:
12 seperate .dat files, each titled something like output_1_x.dat, output_2_x.dat, etc.
each file is actually one piece of a whole that was seperated and processed
each .dat file is approx. 3.9 GB
Here's what I need to do:
create a single file containing all the data from each seperate file, i.e. I need to recreate the original file.
call this complete output file something like output_final.dat
it has to be done in MATLAB, there are no other alternatives (actually there maybe; see note below)
What is implied:
I will have to fread each 3.9 GBfile into chunks or packets, probably 100 mb at a time (using an imbedded loop?)
these packets will have to be read then written sequentially
after one file is read then written into output_final.dat, the next file is automatically read & written (the master loop).
Well, that's pretty much it. I did a search for 'merging mulitple files' and found this. That isn't exactly what I need to do...I don't need to take part of a file, or data from files, and write it to a new one. I'm simply...concatenating...? This would be simple in Java or Perl, but I only have MATLAB as a tool.
Note: I am however running KDE in OpenSUSE on a pretty powerful box. Maybe someone who is also an expert in terminal knows a command/script to do this from the kernel?
So on this site we usually would point you to whathaveyoutried.com but this question is well phrased.
I wont write the code but i will give you how I would do it. So first I am a bit confused about why you need to fread the file. Are you just appending one file onto the end of another?
You can actually use unix commands to achieve what you want:
files = dir('*.dat');
for i = 1:length(files)
string = sprintf('cat %s >> output_final.dat.temp', files(i).name);
unix(string);
end
That code should loop through all the files and pipe all of the content into output_final.dat.temp (then just rename it, we didn't want it to be included in anything);
But if you really want to use fread because you want to parse the lines in some manner then you can use the same process:
files = dir('*.dat');
fidF = fopen('output_final.dat', 'w');
for i = 1:length(files)
fid = fopen(files(i).name);
while(~feof(fid))
string = fgetl(fid) %You may choose to parse the string in some manner here
fprintf(fidF, '%s', string)
end
end
Just remember, if you are not parsing the lines this will take much much longer.
Hope this helps.
I suggest using a matlab.io.matfileclass objects on two of the files:
matObj1 = matfile('datafile1.mat')
matObj2 = matfile('datafile2.mat')
This does not load any data into memory. Then you can use the objects' methods to sequentialy save a variable from one file to another.
matObj1.varName = matObj2.varName
You can get all the variables in one file with fieldnames(mathObj1) and loop through to copy contents from one file to another. You can then clear some space by removing the copied fields. Or you can use a bit more risky procedure by directly moving the data:
matObj1.varName = rmfield(matObj2,'varName')
Just a disclaimer: haven't tried it, use at own risk.
I'm having problems reading in from a txt file in matlab. The txt file is an online review, so the delimeter I want to use is just a single whitespace. I've tried using dlmread, textscan and textread but can't seem to get it to work. I want each word in the txt file to be in a seperate cell in an array. How do I go about this?
Thanks
EDIT, this is the txt file
My husband and I satayed for two nights at the Hilton Chicago,and
enjoyed every minute of it! The bedrooms are immaculate,and the
linnens are very soft. We also appreciated the free wifi,as we could
stay in touch with friends while staying in Chicago. The bathroom was
quite spacious,and I loved the smell of the shampoo they provided-not
like most hotel shampoos. Their service was amazing,and we absolutely
loved the beautiful indoor pool. I would recommend staying here to
anyone.
textread('your_filename', '%s') should work.
If all else fails (other answers already seem good, but you specifically said the functions they proposed do not work), try something like this:
fid = fopen('test.txt');
for i = 1:1000
A{i} = fscanf(fid,'%s',1);
end
fclose(fid)
Just make sure your loop is long enough to read every word.
Does anyone know if it's possible to automatically write a figure out to a .eps file in MATLAB?
I'm running a script that produces a large number of graphs, and it'd be nice if I didn't have to manually save each one!
print function does that:
Print figure or save to specific file format...
print(filename,formattype) saves the current figure to a file using the specified file format, such as print('BarPlot','-dpng'). If the file name does not include an extension, then print appends the appropriate one.
print(filename,formattype,formatoptions) specifies additional options that are available for some formats.
print prints the current figure to the default printer...
print or saveas will do the trick.
saveas(fig_handle, 'filename','eps')
print('-deps',fig_handle)
print -deps 1
If you want to specify the output file name, you're better off using saveas.
This was answered in this other question, using the PRINT command. Although that question dealt with making .tiff images, it should be straightforward to modify the code given in those answers to write a .eps.
Suppose, you are generating N numbers of figures in a loop, then you should try the command line:
saveas(gca,sprintf('Figure%02d.pdf',N )); it produces N figures Figure1.pdf - FigureN.pdf
saveas(gca,sprintf('Figure%02d.eps',N )); it produces N figures Figure1.eps - FigureN.eps
in place of gca one can use gcf also. First command line is a better solution.
Hope this will solve your issue.