fail to delete files using the delete command in R2018a

Hi, everyone,

The current dir is F:\Test

I tested to delete files using the following commands:

TestName = 'F:\Test\Test\Test.xlsx'
delete TestName

But it failed to work:

When I set the current dir to F:\Test\Test and using the following commands:

TestName = 'Test.xlsx'
delete TestName

It also failed to work:

But when I using the delete 'Test.xlsx' command, it succeeded:

Does anyone have the same problem or who can tell me why?

Thank you very much in advance.

[Stephen23]

"Does anyone have the same problem or who can tell me why?"

Because you are using command syntax, which interprets all trailing inputs as literal strings. So when you enter this:

Delete TestName

it is exactly equivalent to this:

Delete('TestName')

Thus none of your examples (except the last one) are trying to delete that file. If you want to use a variable as an input argument to a function then you will need to use function syntax, as Walter Roberson showed. Note also that none of the examples in the MATLAB help show command syntax being used with an input argument.

Answer 1

[Walter Roberson]

delete(testname)

For an explanation see https://www.mathworks.com/help/matlab/matlab_prog/command-vs-function-syntax.html

[Sihem Nour El Houda]

Hello , sir . I tried to use the delete command many times but it wouldn't work. I can't seem to understand why as I followed many examples. What I'm working on is : if an image verifies a condition that is defined, delete the file !

The code runs but the image file is always present in the folder !

I would really appreciate your help with this as I need it to loop through tens of images prior to the training of a CNN.

Thanks in a advance

[Walter Roberson]

Please post some code for us to look at.

Answer 2

[Jianfei]

Deleting a file may fail even if that file has not being used. I tried to use Java io functions to delete files, but it still can't guarantee success.

My wordaround:

Write a delete function contains a while loop to check if the file has already been deleted. Use an expiration time as input.

It can't guarantee 100% success, but greatly increase your success rate.