MatLab - accessing subfolders of folders saved as variables - matlab

I have the following code which can create a directory within a selected folder:
photos_dir = 'C:\Users\Bob\Photos';
mkdir(photos_dir,'Christmas 2015')
I'd like to then be able to save an image to this folder, I think using something like:
imwrite(img,Christmas 2015,'jpg')
However, this does not select the "Christmas 2015" folder which is in the "\Photos" directory. How can I make the image be written to this location?

First of all, you're going to have a syntax error since Christmas 2015 should at least be a string. But other than that, if you want to save a file in a particular location (other than the current working directory), you need to provide the full path to the file location.
To do this, you need to use fullfile to combine all of your directory and file names together into a full file path.
image_name = fullfile(photos_dir, 'Christmas 2015', 'yourphoto.jpg');
imwrite(img, image_name, 'jpg')

Related

MATLAB - Get current path and then use it to navigate to a different folder

I have a bunch of codes that are currently stored on my local machine. There are two folders, one called "Resources" and another called "src". There is one main script that needs to be run called "main.m" in "src" which calls files from "Resources".
If I copy this whole thing onto a new computer, the paths will change and MATLAB may not be able to find "Resources" anymore. I know that relative to "main.m", I need to go up one level and then into "Resources".
What is the best way of getting MATLAB to point to "Resources"?
I am currently trying along the lines of
P = mfilename('fullpath')
which gives the path for main.m. Now, I want to navigate from here, one folder up and then into "Resources". Or if there is a better way, please let me know.
Eventually, I want to extend it to work for multiple folders "Resources1", "Resources2" etc. so MATLAB needs to be able to navigate to the right folder.
You can get it like:
fullfile(fileparts(mfilename('fullpath')), '..', 'Resources');
Explanation:
mfilename('fullpath') will return the full path and name of the
M-file in which the call occurs, without the extension
fileparts will return the path of the passed file (only the containing directory)
fullfile will build the full directory specification from the folder names passed (Note: '..' always means the parent directory)
Based on this it is quite simple to write a function that gets the sibling directory of the directory containing the file:
getSiblingOfParentDirectory.m
function siblingDirPath = getSiblingOfParentDirectory(filepath, siblingDirName)
siblingDirPath = fullfile(fileparts(filepath), '..', siblingDirName);
end
then to use it in an M-file:
for i = 1:3
disp(getSiblingOfParentDirectory(mfilename('fullpath'), ['Resources', num2str(i)]));
end
Sample output:
D:\pathtest\Resources1
D:\pathtest\Resources2
D:\pathtest\Resources3
You can try the following:
ResourcesFolder = strrep(mfilename('fullpath'), 'src\main', 'Resources');
addpath(ResourcesFolder);
%%Your code here where you need those files
rmpath(ResourcesFolder);
Which is fully dependant on the names of your folders & files of course. Basically "addpath" enables you to access the files in the mentioned directory by adding it to the search path, and "rmpath" does the exact opposite.
Also, if you literally want to navigate to a folder present on one level up, you can execute the following:
cd ..\Resources
Which goes one level up, searches for the folder 'Resources', then changes the current directory to that folder .

delete files with numbered names in matlab directory

I'm new to matlab and I've wrote a code that implements the gamma function for image processing. I generate around 300 photos named '001.jpg' to '300.jpg' and then use ffmpeg to make a video.
In the end, I only need the video result and need a command to delete all the photos generated in the directory! is there a way to do that?
If you want to remove all .jpg files in the current directory you can use the delete command with a wildcard (*)
delete('*.jpg')
If the files live in a folder other than the current directory, you can specify the directory in this way.
folder = '/path/to/my/files';
delete(fullfile(folder, '*.jpg'))
If you want to limit it to just files that have number filenames, you could do something like the following
files = dir('*.jpg');
filenames = regexp({files.name}, '^[0-9]+\.jpg$', 'match', 'once');
filenames = cellstr(cat(1, filenames{:}));
delete(filenames{:})
Adding to Suever's answer (not allowed to comment yet):
Assuming you already know the names of the images you're creating, you could save your script a 'trip' to the folder and back by creating the filenames list yourself thus:
for i=1:numOfImages
filenames(i)={strcat(num2str(i),'.jpg')};
end
delete(filenames{:})

temporary remove all of the added paths in matlab

I have added a lot of paths to matlab and now I want to share my code, but I don't know exactly which function (in which path) I should add to my shared code. Each time I need to add a missing function and it is really bothering for me and the users who are using the code.
So, I would like to restore the matlab path to its original case. Is there any way to do this in matlab? I also want to keep a backup of my current added path in a .m file and use it later when I am done.
To restore the path to default value - http://www.mathworks.com/help/matlab/ref/restoredefaultpath.html
restoredefaultpath sets the search path to include only folders for
MathWorks® installed products. Use restoredefaultpath when you are
having problems with the search path.
restoredefaultpath; matlabrc sets the search path to include only
folders for MathWorks installed products and corrects search path
problems encountered during startup.
And to save the current path - http://www.mathworks.com/help/matlab/ref/savepath.html
savepath updates the MATLAB® search path for all users on the system
so that the path can be reused in a future session. savepath saves the
search path to the pathdef.m file that MATLAB located at startup, or
to the current folder if a pathdef.m file exists there.
Or you can just store path in variable p = path; and restore it later path(p);. If the path is saved into pathdef.m the call of pathdef returns the string that can be used to set the saved path.

How to write relative path in MATLAB?

I need to read a group of dat files so when I do this it is working all right.
list_of_files=dir(fullfile('/home/username/Desktop/Old/MTP/Generate/schemes/o33smnpimp/data/', '*.dat'));
The thing is I want to do this for number of schemes (like o33smnpimp) where every scheme folder has a data folder so I tried something like this but it's not working. What could be the problem?
list_of_files=dir(fullfile('../data/', '*.dat'));
My matlab file lies in o33smnpimp folder.
.. indicates the parent directory, . the current directory. your code looks in /home/username/Desktop/Old/MTP/Generate/schemes/ for the sub directory data, assuming your working directory is /home/username/Desktop/Old/MTP/Generate/schemes/o33smnpimp.
Use
list_of_files=dir(fullfile('./data/', '*.dat'));
or
list_of_files=dir(fullfile('data', '*.dat'));

access folders and get files

I start with Matlab and would like to know how could I access to a folder and get contents to access files and read them.
I have a variable in workspace tmpfolder that is equal to 'path to folder' but I don't find how could I make dir(tmpfolder) and get files, browse any file content to get a string value...
I would start with dir() and fopen().
More generally, try starting at the beginning: Working with Files and Folders.
If you have an image file in jpeg format in another folder named myimage and a text file called mytext, use:
prefix_image='myimage';
prefix_data='mytext';
fileformat='.jpg';
dataformat='.txt';
folder='C:\Users\khaled\Documents\MATLAB\';
image = imread(strcat(folder,prefix_image,fileformat));
data=textread(strcat(folder,prefix_data,fileformat),'%f');