How to replace the empty cells in a cell array by a 4-bits string?

Hello,

How to replace the empty cells " [ ] " in the attached matrix to a 4-bits string we can convert the whole array matrix to double.

For example,

if we have thw following row:

[ '0001', '0101' , '1010', [ ], [ ], [ ], '1111']

it becomes:

[0,0,0,1,0,1,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1]

Answer 1

[Akira Agata]

How about the following?

load('Key.mat');
idx = cellfun(@isempty,Key); % Find the indexes of empty cell
Key(idx) = {'0000'};         % Replace the empty cells with '0000'

[Sarah A]

Thank you :)

[Thomas Carpenter]

Using the optimised 'length' operation for cellfun - i.e ~cellfun('length',Key) - is generally more efficient than calling @isempty.

[Walter Roberson]

Timing test:

Key = num2cell(rand(100,100));
whos Key

  Name        Size               Bytes  Class    Attributes

  Key       100x100            1280000  cell               

Key(randi(100*100,50,1)) = {[]};

t1 = timeit(@() cellfun(@isempty,Key), 1)

t1 = 0.0055

t2 = timeit(@() ~cellfun('length',Key), 1)

t2 = 8.2372e-05

So the 'length' version is indeed faster.

Answer 2

[Stephan]

load('Key.mat');
Key1 = Key(:);
Key1 = reshape(replace(string(char(Key1{:})),"    ","0000"),size(Key,1),size(Key,2));

results in a string array filing up all empty elements with "0000".

[Sarah A]

it is not working, I got this error:

Undefined function 'replace' for input arguments of type 'char'.

[Walter Roberson]

Which MATLAB version are you using? R2016a or earlier likely.