How to change a certain array cell depending on its length

Hello,

I currently have this very simple code:

if strlength(A) >= 250 
    A = [];
end

My objective is for every cell that A has which is larger than 250 characters, make that specific array row 0.

e.g. ( The 12th row of array A has more than 250 characters in it, thus it should become 0 after the code runs)

However, my problem is that the program just skips over the if statement as if it's false when in reality I have characters which go beyond 250.

I tried implementing the cellfun into this as well just in case every row of the array isn't being checked.

if cellfun(@strlength, A)>=250
    A = [];
end

but still the same problem.

I know the if statement isn't false because upon running just

strlength(A) >= 250

I have a whole list of 0's (which corespond to characters under 250) and some 1's (which are those above 250)

Answer 1

[Adam Danz]

If 'A' is a cell array of character vectors and you'd like to replace cells that have a length greater than 250 with an empty char array,

A(strlength(A)>250) = {''};

For string arrays (ie, ["abc", "def", "ghi" ...],

A(strlength(A)>250) = "";

[Walter Roberson]

Nice use of string() facilities.

[Nom]

Adam you've done it again, it works!

Right before you posted the answer, I was messing around with using what you used.

But I was doing it this way instead

A(strlength(A)>250) = '';

But this ended up just deleting those with a character length larger than 250 lol.

All of this was gotten through here for anyone who wants to know:

https://www.mathworks.com/help/matlab/matlab_prog/find-array-elements-that-meet-a-condition.html

Thanks again Adam!

[Adam Danz]

Thanks & thanks!

@Nommah, if you were working with string arrays, you could use that line of code (I updated my answer to provide an example of that, too).

[Nom]

Thanks! I'm just working with a cell full of characters.

I was thinking of making this more advanced, though I'm not sure if it's possible without getting really complicated.

This is what I have so far below:

A(strlength(A)>250) = strrep(A,'C:\Desktop\','');

So in essence I would want to find the cells whose character length is greater than 250 and then apply a string replace which looks inside of A to find the string "C:\Desktop\" and replace that with just nothing (so deleting it).

However, I get the error of:

In an assignment  A(:) = B, the number of elements in A and B must be the same.

I'm not sure if it's because I'm mixing up my string functions with the character arrays I'm working with.

[Adam Danz]

A(strlength(A)>250) = strrep(A(strlength(A)>250),'C:\Desktop\',''); 

[Nom]

You're actually a genius, I don't know how you know so much about Matlab!

Solving everyone of my problems.

[Adam Danz]

If A is a cell array of paths and you're trying to eliminate the paths and keep the filenames, this would be a better approach:

[~,filenames] = cellfun(@fileparts,A,'UniformOutput',false)

[Nom]

I've decided to use your first method, just because I understand it much more clearly.

Main reason I'm doing this is because excel has a 255 column width limit which gives an error if I try query a file whose path is more than 255 characters. By just removing the file path's header (which just removes where the file was searched for) I can still retain the important information of where the file is located.

Thank you so much though Adam,

I really really appreciate all the help you provide.

Answer 2

[Fabio Freschi]

mask = strlength(A) > 250;
A(mask) = cellfun(@(i) '', A(mask), 'uniform', 0);

using a strategy similar to the solution used here https://www.mathworks.com/matlabcentral/answers/366514-using-conditional-statements-inside-cellfun

[Nom]

Thank you for your answer Sir,

I've decided to use

A(strlength(A)>250) = {''};

As it's just one simple line of code which acomplishes exactly what I needed it to do.

Thank you so much though!