I have 31 models an I want to save each one in a specific file
this is my matlab function
formatspec='model%d'
for k = 1:length(libsvmFiles)
baseFileName = libsvmFiles(k).name;
fullFileName = fullfile(myFolder, baseFileName);
[labels train]=libsvmread(fullFileName);
model=svmtrain(labels,train, '-t 2 -h 0');
file=sprintf(formatspec,k);
save file model;
but the problem is only the first file is saved and its name is 'file' tha's mean the value of the variable file is not evaluated
how can I solve this problem ?
As many Matlab functions, save can be used in function form (save(...)) or in command form (save ...). In the command form that you use, all the arguments are interpreted as strings. That means
save file model
is equivalent to
save('file', 'model')
For the second argument that is correct, because you want to refer to the variable with the name "model". For the first argument it is wrong, because you want to refer to the file name contained in the variable file. The correct syntax to use is therefore
save(file, 'model')
You're missing the parens for the save function. The model variable also needs to be listed as a string since you need to tell the save function the name of the variable, not the variable itself. See Matlab's documentation.
save(file, 'model');
Additionally you don't have an end to your for loop shown, which normally would just throw an error -- however later code might cause this loop to instead only run once. Otherwise you should check your libsvmFiles variable as it might be only length 1 or not be an array.
Related
I am creating a matlab application that is analyzing data on a daily basis.
The data is read in from an csv file using xlsread()
[num, weather, raw]=xlsread('weather.xlsx');
% weather.xlsx is a spreadsheet that holds a list of other files (csv) i
% want to process
for i = 1:length(weather)
fn = [char(weather(i)) '.csv'];
% now read in the weather file, get data from the local weather files
fnOpen = xlsread(fn);
% now process the file to save out the .mat file with the location name
% for example, one file is dallasTX, so I would like that file to be
% saved as dallasTx.mat
% the next is denverCO, and so denverCO.mat, and so on.
% but if I try...
fnSave=[char(weather(i)) '.mat'] ;
save(fnSave, fnOpen) % this doesn't work
% I will be doing quite a bit of processing of the data in another
% application that will open each individual .mat file
end
++++++++++++++
Sorry about not providing the full information.
The error I get when I do the above is:
Error using save
Argument must contain a string.
And Xiangru and Wolfie, the save(fnSave, 'fnOpen') works as you suggested it would. Now I have a dallasTX.mat file, and the variable name inside is fnOpen. I can work with this now.
Thanks for the quick response.
It would be helpful if you provide the error message when it doesn't work.
For this case, I think the problem is the syntax for save. You will need to do:
save(fnSave, 'fnOpen'); % note the quotes
Also, you may use weather{i} instead of char(weather(i)).
From the documentation, when using the command
save(filename, variables)
variables should be as described:
Names of variables to save, specified as one or more character vectors or strings. When using the command form of save, you do not need to enclose the input in single or double quotes. variables can be in one of the following forms.
This means you should use
save(fnSave, 'fnOpen');
Since you want to also use a file name stored in a variable, command syntax isn't ideal as you'd have to use eval. In this case the alternative option would be
eval(['save ', fnSave, ' fnOpen']);
If you had a fixed file name (for future reference), this would be simpler
save C:/User/Docs/MyFile.mat fnOpen
I have different mat files w/ distinct names. So I am using a function whose input is the mat file. I used "varargin" to enable the function to take different files.
function bestfunc(varargin)
data = load(varargin, '-mat');
end
when I try to call the function like
bestfunc('matrix777')
Matlabe comes up w/ this error:
Error using load
Argument must contain a string.
Any ideas?
you have to get the names of the files. You can use dir() to do that.
dir('*.mat') % will return information about all .mat files in the folder
The output is a struct with more information for each file. TO get the names try
names=struct2cell(dir('*.mat'));
names=names(1,:);
now names is a cellarray with the names of all *.mat files of your folder. TO load data from each go for
for i=1:length(names)
bestfun(names{i});
end
Since you're only passing one argument, you don't need varargin, which is used when you may have a variable number of arguments to a function.
Just use a normal variable name like matname:
function bestfunc(matname)
data = load(matname, '-mat');
end
Then call it as you did before:
bestfunc('matrix777')
for m = 1:length(lst_region)
out=cellfun(#(x) str2double(x(1:strfind(x,'_')-1)),lst_region(m));
str=[num2str(out(1)) '.mat'];
save ( str ,distance);
end
Error using save
Argument must contain a string. Line 3
I want to save files like '1.mat' '2.mat' etc.. but i have error can you please help me to fix it
If distance is a variable in your workspace, you will have to call save(str, 'distance');. You have to enter the name of the variable, not the variable itself.
%select all .mat files
oar = dir('*oar.mat'); n = {oar.name};
%loop through files
for l=1:length(oar);
load pat_oar(l) %<---this is the .mat file with variable filename
clear ...
end
How do I write some Matlab script that will read in one .mat file after another...
You file names are stored in n, so you should be able to do:
for l=1:length(oar)
load(n{l})
end
Use the functional form. Instead of:
load pat_oar{I}
Use
load(pat_oar{I})
Calling a Matlab command using the unix-style syntax (i.e. command arg1 arg2) is just syntax shorthand for the more verbose syntax of command('arg1','arg2'). It's a pretty common trick to use the more verbose syntax anytime an argument is stored in a variable.
I'm going to read some function from a Unicode text file in matlab and calculate there answer with my own variables. first i use fopen to read the text file, then what should i do to convert each line of that text file to a function? for example the func.txt contains:
(x^2)-3y
sin(x+z)+(y^6)
and i need to write an m.file which read func.txt and process that like this:
function func1[x,y] = (x^2)-3y
function func2[x,y,z] = sin(x+z)+(y^6)
Preamble: if your final aim is to use those functions in matlab (i.e. evaluate them for some values of x,y,...), I would rather suggest the following approach that looks more robust to me.
In principle, in fact, you don't need to manipulate the file funct.txt to evaluate the functions defined therein.
First problem: each line of your file funct.txt must define an inline function.
Say that the first function (i.e., the first line) of the file funct.txt has been copied into a string str,
str = '(x^2)-3y',
you can obtain a function from it using the command inline:
f1 = inline(str,'x','y');
which gives to you (matlab output)
f1 =
Inline function:
f1(x,y) = (x^2)-3y.
Now you can use f1 just calling it as f1(x,y), for whatever values x,y.
Second problem: you have to parse your file funct.txt to obtain the strings str containing the definitions of your functions. That's easier, you may want to consider the function fgets.
Third problem: the functions in funct.txt may depend on 2,3 (or more?) independent variables. As far as I know there is no easy way to parse the string to discover it. Thus, you may want to define each inline function as depending on all your independent variables, i.e.
f1 = inline('(x^2)-3y','x','y','z');
the variable z will play no active role, by the way. Nonetheless, you need to specify a third dummy parameter when you call f1.