I have some data in a cell array,
data2={[50,1;49,1;26,1];...
[36,2;12,2;37,2;24,2;47.3,2];}
and names in another cell array,
names2={'xxx/01-ab-07c-0fD3/0';'xxx/01-ab-07s-0fD3/6';}
I want to extract a subset of the data,
data2_subset=data2{1,:}(:,1);
then a temporary file name,
tempname2=char(names2(2));
an save the subset to a text file with
save (tempname2, 'data2_subset', '-ASCII');
But I get this error message: _
Error using save
Cannot create '6' because 'xxx/01-ab-07s-0fD3' does not exist.
To try to understand what is happening, I created a mock dataset with simpler names:
names={'12-05';'14-03'};
data={[50,1;29,1;25,1];[35,2;22,2;16,2;38,2];[40,3;32,3;10,3;44,3;43,3];};
data_subset=data{1,:}(:,1);
tempname=char(names(2));
save (tempname, 'data_subset', '-ASCII');
in which case the save command works properly.
Unfortunately I still do not understand what the problem is in the first case. Any suggestions as to what is happening, and of possible solutions?
MATLAB is interpreting the the forward slashes (/) as directory separators and 6 as the intended file name (your second example doesn't have this slash problem).
Since the relative directory tree xxx/01-ab-07s-0fD3/ doesn't exist, MATLAB can't create the file.
To solve the problem, you can either create the directories beforehand using mkdir():
>> pieces = strsplit(tempname2,'/');
>> mkdir(pieces{1:2});
>> save(tempname2, 'data2_subset', '-ASCII');
or replace the / with some other benign symbol like _:
>> tempname3= strrep(tempname2,'/','_');
>> save (tempname3, 'data2_subset', '-ASCII');
(which works for me).
Related
There are two parts of my query
1) How to save different fields of structures as separate files(each file containing only named field of structure )?
2) Forcing save command to create directories in the save path when intermediate directories do not exist?
For first part:
data.a.name='a';
data.a.age=5;
data.b.name='b';
data.b.age=6;
data.c.name='c';
data.c.age=7;
fields=fieldnames(data);
for i=1:length(fields)
save(['E:\data\' fields{i} '.mat'],'-struct','data');
end
I want to save each field of struct data as a separate .mat file. So that after executing the loop, I should have 3 files inside E:\data viz. a.mat,b.mat and c.mat and a.mat contains only data of field 'a', b.mat contains only data of field 'b' and so on.
When I exeucte the above code, I get three files in my directory but each file contains identical content of all three variables a, b and c, instead of individual variables in each file.
Following command does not work:
for i=1:length(fields)
save(['E:\data\' fields{i} '.mat'],'-struct',['data.' fields{i} ]);
end
Error using save
The argument to -STRUCT must be the name of a scalar structure variable.
Is there some way to use save command to achieve my purpose without having to create temporary vaiables for saving each field?
For Second Part:
I have large number of files which need to stored in a directory structure. I want following to work.
test='abcdefgh';
save(['E:\data\' test(1:2) '\' test(3:4) '\' test(5:6) '\result.mat'])
But it showing following error
Error using save
Cannot create 'result.mat' because 'E:\data\ab\cd\ef' does not exist.
If any intermediate directory are not present, then they should be created by save command. I can get this part to work by checking if directory is present or not using exist command and then create directory using mkdir. I am wondering if there is some way to force save command to do the work using some argument I am not aware of.
Your field input argument to save is wrong. Per the documentation, the format is:
'-struct',structName,field1,...,fieldN
So the appropriate save syntax is:
data.a.name='a';
data.a.age=5;
data.b.name='b';
data.b.age=6;
data.c.name='c';
data.c.age=7;
fields = fieldnames(data);
for ii = 1:length(fields)
save(['E:\data\' fields{ii} '.mat'], '-struct', 'data', fields{ii});
end
And no, you cannot force save to generate the intermediate directories. Check for the existence of the save path first and create it if necessary.
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 am studying Suever's answer where I do not understand its application with fullfile in Code 1.
Code 1
filename=strcat('/Users/masi/Images/', 'p.1');
save(fullfile(filename,'.mat'),'time');
saveas(her, fullfile(filename,'.png'));
Output
Error using save
Cannot create '.mat' because '/Users/masi/Images/p.1' does not
exist.
Code 2
filename=strcat('/Users/masi/Images/', 'p.1');
save(strcat(filename,'.mat'),'time');
saveas(her, strcat(filename,'.png'));
Success!
Change made based on Daniel's answer
filenameMat=fullfile('/Users/masi/Images/', 'p.1', '.mat');
save(filenameMat,'time');
but still getting
Error using save
Cannot create '.mat' because '/Users/masi/Images/p.1.mat' does not
exist.
I do not understand.
Why is code 1 giving the error?
You are using fullfile for a wrong application. The documentation clearly explains the parameters:
Folder and file names, specified as strings and cell arrays of strings.
You input a filename without extension and a file extension, hat is not what fullfile is made for. It will insert a file separator between both:
>> fullfile('foo','.bar')
ans =
foo\.bar
fullfile would be the right function to construct filename.
I have an application that translates the .csv files I currently have into the correct format I need. But, the files I that I do have seem to have '"' double quotes around them, as seen in this image, which will not work with the program. As a result, I'm using this command to remove them:
for m = 1:currentsize(1)
for n = 1:currentsize(2)
replacement{m,n} = strrep(current{m,n}, '"', '');
end
end
I'm not entirely sure that this works though, as it spits this back at me as it runs:
Warning: Inputs must be character arrays or cell arrays of strings.
When I open the file in matlab, it seems to only have the single quotes around it, which is normal for any other file. However, when I open it in notepad++, it seems to have '"' double quotes around everything. Is there a way to remove these double quotes in any other way? My code doesn't seem to do anything as seen here:
After using xlswrite to write the replacement cell-array to a .csv file, one appears corrupted. Any idea why?
So, my questions are:
Is there any way to remove the quotes in a more efficient manner or without rewriting to a csv?
and
What exactly is causing the corruption in the xlswrite function? The variable replacement seems perfectly normal.
Thanks in advance!
Regarding the "corrupted" file. That's not a corrupted file, that's an xls file (not xlsx). You could verify this opening the text file in a hex editor to compare the signature. This happens when you chose no file extension or ask excel to write a file which can't be encoded into csv. I assume it's some character which causes the problems, try to isolate the critical line writing only parts of the cell.
Regarding your warning, not having the actual input I could only guess what's wrong. Again, I can only give some advices to debug the problem yourself. Run this code:
lastwarn('')
for m = 1:currentsize(1)
for n = 1:currentsize(2)
replacement{m,n} = strrep(current{m,n}, '"', '');
if ~isempty(lastwarn)
keyboard
lastwarn('')
end
end
end
This will launch the debugger when a warning is raised, allowing you to check the content of current{m,n}
It is mentionned in the documentation of strrep that :
The strrep function does not find empty strings for replacement. That is, when origStr and oldSubstr both contain the empty string (''), strrep does not replace '' with the contents of newSubstr.
You can use this user function substr like this :
for m = 1:currentsize(1)
for n = 1:currentsize(2)
replacement{m,n} = substr(current{m,n}, 2, -1);
end
end
Please use xlswrite function like this :
[status,message] = xlswrite(___)
and check the status if it is zero, that means the function did not succeed and an error message is generated in message as string.
I am writing a program to plot graphs in a loop and I want to save each graph that comes out as a .jpg file with a variation of the file name. Here is my code for saving the graphs:
filename = strcat('WI_Pollutants_', D(i,6), '_200706_O3');
saveas(gcf, filename, 'jpg');
The saved file should come out as the following with D(i,6) changing each iteration of the loop.
WI_Pollutants_003-0010_200706_O3.jpg
However, I'm running an error: (Maybe it has to due with saveas wanting a string only?)
Error using saveas (line 81)
Invalid filename.
saveas only accepts characters as the filename. But when filename was created, strcat made it a cell array. Therefore, the filename needs to be converted to a character array.
filename = char(strcat('WI_Pollutants_', D(i,6), '_200706_O3'));
saveas(gcf, filename, 'jpg');
This solves the problem.
I think your D{i,6} is ending up wrapped up as an array, from this line:
D{i,6} = [num2str(D{i,6}) '-' num2str(D{i,7})];
To solve this, just removing the []'s
D{i,6} = num2str(D{i,6}) '-' num2str(D{i,7});
I think what happened is your D{i,6}=['someString'], and concatinating added in the []'s that werent' desired.
As a check, if something like this happens again, just fprintf(filename) right before use, and look at what comes out. I suspect you'll find the issue there. You can always remove the print statement later on.