HELP with Undefined variable, size of the indicated variable changes with each loop iteration.
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Hello, i have been running a code during some time and it worked. However now, i am trying to run it and it does not run because of this error message:
??? Undefined function or variable 'files'.
Error in ==> after_all at 20 coord = regexp(files,'\d+(\.\d+)?','match'); % It extracts the coordinates from the name of each file
The problem is the variable files (The size of the indicated variable or array appears to be changing with each loop iteration) it says...
Can anyone help me, please?
This is my code:
clear all; % clear all variables
close all; % close all plot windows
clc; % clear the command window
workfolder='C:\Users\Jorge\Desktop\Airfoil_BASELINE_Measurements\Airfoil_BASELINE_Measurements\Re140k00deg'; % It defines the folder (rpm or Re) to run
folders=[ % It indicates that in the folder selected we are interested in the Hot Wire measurements
{'cdaq2mod2_ai0-hw\'}
{'cdaq2mod2_ai1-hw\'}
];
file_data=dir([workfolder folders{1} 'x*.dat']); %Inside the hot wire measurements we look for all the files with an "x" in its name
for i=1:length(file_data);
files(i,1)={file_data(i).name}; % It creates a variable with all the names of the files
end
% files=[
% {'x_+0.000mm_y_+0.000mm_z_+0.000mm.dat'}
% {'x_+0.000mm_y_+5.000mm_z_+0.000mm.dat'}
% ];
coord = regexp(files,'\d+(\.\d+)?','match'); % It extracts the coordinates from the name of each file
xyzCoords = cell2mat(cellfun(@(x)str2num(char(x))',coord,'UniformOutput',false)); % It organize the coordinates properly
采纳的回答
Guillaume
2015-1-27
The error is Undefined function or variable 'files'. files is defined inside your for loop. So if it is undefined after the loop that means your loop didn't execute. The only reason for your loop not to execute is that length(file_data) is 0, i.e. no file was found.
Morale of the story: when interacting with the filesystem (or any data outside your program control, like user input), always check that you're getting what you're expecting. In this case, do check that there is at least one file.
Note: You don't need a loop to transform the structure returned by dir into a cell array of filenames:
files = {file_data.name};
works just as well. It would also have avoided the undefined variable error in regexp (which would just have returned an empty cell array. Most likely, another error would occur later because you haven't designed your code to cope with no file being found.
4 个评论
Peter
2015-1-27
Peter
2015-1-27
I suspect you're missing a trailing slash at the end of workfolder. As a result, you're searching the content of the folder Re140k00degcdaq2mod2_ai0-hw.
The best way to avoid this sort of problem is not to use string concatenation, but path combining function, that is fullfile, which adds '/' when needed:
file_data = dir(fullfile(workfolder, folders{1}, 'x*.dat')); %what about folders{2:end}?
Again, all this would become obvious if you design your code to report on problem, e.g.:
fullpath = fullfile(workfolder, folders{1});
filepattern = 'x*.dat'
file_data = dir(fullfile(fullpath, filepattern));
if isempty(file_data)
error('no file matching pattern '%s' was found in folder '%s', filepattern, fullpath);
end
Peter
2015-1-27
更多回答（1 个）
Alessandro Masullo
2015-1-27
编辑：Alessandro Masullo
2015-1-27
The variable files is a cell array, and you are trying to refer it as a matrix. You should use files{i} instead of files(i,1) when you want to assign it:
for i=1:length(file_data);
files{i} = file_data(i).name;
end
5 个评论
Peter
2015-1-27
Alessandro Masullo
2015-1-27
I tried this code, and it works:
file_data = dir('*.*');
for i=1:length(file_data);
files{i} = file_data(i).name;
end
What is the error and where do you get it?
Peter
2015-1-27
Peter
2015-1-27
Guillaume
2015-1-27
@Alessandro,
y{i} = x
and
y(i) = {x}
are equivalent, when y does not exists or is already defined as a cell array.
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