MATLAB: Collapsing nested cell array values into simple numerical array

cell arrayMATLAB

I have used regexp to find some numbers in each element of a cell array. However, the result of the regexp is a nested cell array such as the following:
>> celldisp(a)
a{1}{1}{1} =
5
a{2}{1}{1} =
36
All I want is to have the result collapsed into the simple numerical array [5 36] but I have been unable to get the right syntax.I have tried things like the following but the nesting seems to cause issues:
>> b=[a{:}{1}{1}]
Expected one output from a curly brace or dot indexing expression, but there were 2 results. 
>> b=cell2mat(a{:}{1}{1})
Expected one output from a curly brace or dot indexing expression, but there were 2 results. 
>> b=cell2mat(a)
Error using cell2mat (line 52)
CELL2MAT does not support cell arrays containing cell arrays or objects.
I could certainly use a loop to iterate through it, but it seems like there should be some very simple syntax that does the trick.

Best Answer

"I have used regexp to find some numbers in each element of a cell array."
If the regular expression only needs to match once, then use the 'once' option to remove one level of nesting.
"but it seems like there should be some very simple syntax that does the trick"
Not really: nesting data in container arrays makes it difficult to access.
>> C = [a{:}];
>> C = [C{:}];
>> V = [C{:}]
V =
    5   36
Read these to know more:
https://www.mathworks.com/help/matlab/matlab_prog/comma-separated-lists.html
https://www.mathworks.com/matlabcentral/answers/320713-how-to-operate-on-comma-separated-lists
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