MATLAB: To Create a Variable with the name of a folder

variable

Hello!

I have a variable called this way;

workfolder='C:\Users\Jorge\Desktop\Work_Christmas\Measurements\rpm_measurements\rpm0800\';

And i would like to create another variable and it is the end of the name of my directory (workfolder), in order to use it with a loop, in this case it would be:

new_variable = rpm0800

How could i do it?

Thanks!

Best Answer

While the question is rather unclear, it seems that the OP wishes to extract the last directory in the filepath string. This can be achieved using fileparts :

>> [A,B] = fileparts(workfolder(1:end-(workfolder(end)==filesep)))
A = 'C:\Users\Jorge\Desktop\Work_Christmas\Measurements\rpm_measurements'
B = 'rpm0800'

Note first this removes any trailing file separator character using the indexing of the workfolder string. An alternative is to use regexp to locate the last directory in the filepath string:

>> regexp(workfolder,'[^/\\]+(?=[/\\]?$)','once','match')
ans = 'rpm0800'

You should also have a good read of the MATLAB wiki, which covers all of these basic usage questions, with handy examples too:

http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F

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MATLAB: Using regular expressions to ignore files starting with a certain set of characters

Okay, just to make it clear to any one else reading this, that this is a bad idea:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

moving on... in my experience, writing regular expressions to NOT match something is logically much more slippery to pin down. Not matching things is an elusive goal with regular expressions, and I have seen several questions on this forum where the OP says something like "but I want to not match THAT character!", and they fail to comprehend that a regular expression is like an octopus and it will happily squeeze around obstructions if it can. I have written some very large regular expressions (e.g. for parsing English language numbers) and my advice would be to avoid doing this: I think you should simply write one expression that simply matches what you need, and then use something like setdiff on the cell array itself (or negate the logical indices) to get the strings that do not match. That would be easier to write the regular expression for, and ensures that you do not miss any cases.

Don't use the regular expression feature at all: simply read all of the names (without any filtering), then use strfind, strncmp, regexp, or whatever, and then a setdiff or negation (depending on the index type). Bingo, two perfectly complementary sets. Something like this:

C = {...} % cell array of strings
X = strncmp(C,'glob',4);
notglob = C(~X);
hasglob = C(X);

MATLAB: Can you help me with this easy loop task

Peter - what are the valid values for x? For example, if x can be just 1 through 9, then you could create your workfolder variable given x as

 for x=1:9
     workfolder = sprintf(['C:\Users\Jorge\Desktop\Work_Christmas\'...
                          'Measurements\rpm_measurements\rpm0%d00\'],x);
     % do other stuff that you have shown above
 end

The "other stuff" would be the code that you have shown in your question, but you would have to modify it so that the output from each of these folders, vel, is saved to (perhaps) a cell array.

Best Answer

Related Solutions

MATLAB: Using regular expressions to ignore files starting with a certain set of characters

MATLAB: Can you help me with this easy loop task

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