how to remove empty cell array contents?

Hello, I've got a cell array, lets say:

R = 
    [ 691x2 double]
    []
    []
    []
    []
    [  12x2 double]
    [  11x2 double]
    []
    []
    [ 112x2 double]
    [  13x2 double]

Does anyone know of a quick way I could remove the non-zero elements of the cell array? This cell array will be a different length and will have a different number of non-zero elements each time, dependent on another loop

Thanks, Jim

Answer 1

[Aurelien Queffurust]

To remove empty cell array contents (title of your question) :

 R(~cellfun('isempty',R))

[Aurelien Queffurust]

Note : Using isempty between quotes is faster than using function handles @isempty

[Jim O'Doherty]

Excellent, makes me feel a little stupid for asking, but thank you very much

Jim

[David Young]

In 2011b, the documentation for cellfun only mentions the string syntax under "backward compatibility".

[Chris Volpe]

Why is using a quoted function name faster than using a function handle? I would have thought that the first thing cellfun did with a quoted name would be to parse it and cache a function handle.

[Jan]

Here 'isempty' is not a quoted function name, but a simple string. The C-implementation of CELLFUN checks the strings mentioned in the documentation and performs the corresponding operations directly. This is much faster than calling a Matlab function for each cell element.

It is very sad, that the fast and efficient string commands are mentioned in the docs as "backward compatibility" only.

Btw, the C-source has been included in the toolbox functions of Matlab 6.5. It was a very good example for the efficient processing of cell elements in a Mex function.

[Daniel Bridges]

>> data(~structfun('isempty',data))

Error using structfun

First input must be a function handle.

[Stephen23]

@Daniel Bridges: that syntax is only in the cellfun documentation. It is not supported by other functions.

[Thulfiqar Hussein]

R = R(~cellfun('isempty',R))

[Prateek Srivastava]

Not able to find out

[Prateek Srivastava]

How to remove null values from cell

[Chintan Modi]

I am also suffering from this problem. I want to delete the empty cells from this "sf" variable (i.e. shown in picture). I wish to delete it from variable so that whenever I try to find column size of the particular row; i'll be able to get only the matrix of that number cell and don't want to count the empty cell. for e.g. if i write

size(sf(3,:),2)
ans i want i.e. 5
but here it shows the 31

can someone help me to solve this problem?

[Jan]

@Chintan Modi: Use the flags to catch the attraction to inapropriate messages, not for posting data concerning your problem.

Please do not attach a new question as a comment to an existing answer. Open a new thread instead.

There is no picture. What is the type of your variable sf? size(sf(3,:),2) replies the size of the array and does not care about the contents of the cell elements.

If you want to count the non-empty cells, use:

sum(~cellfun('isempty', sf(3, :))

Answer 2

[David Young]

Rnew = R(~cellfun(@isempty, R))

[Harold]

I'm also trying to remove empty cells from a matrix but I can't figure out how to maintain the order for each row and column.

D=

{[-24.7697910000000,-15.8191235000000],[],[-12.6771670000000,20.4587480000000],[];[],[-20.6771670000000,-3.54125200000000],[-11.9803417500000,-14.5401785500000],[];[],[-20.6771670000000,-3.54125200000000],[4.32283300000000,-1.04125200000000],[];[],[13.0196582500000,-12.0401785500000],[],[-24.7697910000000,-15.8191235000000];[-11.9803417500000,-14.5401785500000],[],[4.32283300000000,-1.04125200000000],[];[],[-12.6771670000000,20.4587480000000],[],[13.0196582500000,-12.0401785500000]}:

I need

[-24.7697910000000,-15.8191235000000] [-12.6771670000000,20.4587480000000]

[-20.6771670000000,-3.54125200000000] [-11.9803417500000,-14.5401785500000]

[-20.6771670000000,-3.54125200000000] [4.32283300000000,-1.04125200000000]

[13.0196582500000,-12.0401785500000] [-24.7697910000000,-15.8191235000000]

[-11.9803417500000,-14.5401785500000] [4.32283300000000,-1.04125200000000]

[-12.6771670000000,20.4587480000000] [13.0196582500000,-12.0401785500000]

[Andrei Bobrov]

D1 = D.';

out = reshape(D1(~cellfun(@isempty,D1)),2,[])';

[Daniel Bridges]

>> data(~structfun(@isempty,data))

Error using structfun

Inputs to STRUCTFUN must be scalar structures.