Using cellfun and regexp question

Hello,

I have a cell called storedSamplerates = 1X9;

Each cell has a string ex:

storedSamplerates{1} = 'SAMPLERATE: 50000'

storedSamplerates{2} = 'samplerate:200000'

etc.....

I am trying to remove the 'SAMPLERATE:' and 'samplerate:' portion of the cells regardless of case, so only the number is left. I can successfully use regexp with 'ignorecase', to remove this in a loop with:

sampleRates = regexp(storedSamplerates{i},'(\d+)','match','ignorecase');

So that im only left with numbers.

sampleRates{1} = '50000';

sampleRates{2} = '200000'

etc....

But I wanted to try using cellfun to have simpler code and have failed:

sampleRates(cellfun(@(x) regexp(x ,'(\d+)','match','ignorecase'),storedSamplerates));

Using cellfun and regexp seems possible,I just dont know where im messing up?

[Stephen23]

Note that because your regular expression does not match any alphabetic characters (it only matches digits) the 'ignorecase' option is completely superfluous. It does nothing, zilch, nada, zero. Get rid of it.

Also the grouping parentheses do nothing. Get rid of them.

Answer 1

[the cyclist]

I think this does what you want.

storedSamplerates{1} = 'SAMPLERATE:    50000';
storedSamplerates{2} = 'samplerate:200000';

cellfun(@(str)regexp(str,'\d*','match'),storedSamplerates)

[m j]

Hey,

Thanks,this does exactly what I wanted!

[Stephen23]

@m j: you picked the slower, more complex solution (1e4 iterations):

Elapsed time is 2.519055 seconds. % this complex answer
Elapsed time is 0.127693 seconds. % my simple answer

Answer 2

[Stephen23]

The simple and efficient solution is to use the 'once' option:

sampleRates = regexp(storedSamplerates,'\d+','match','once');
%                    ^^^^^^^^^^^^^^^^^ entire array, no indexing!

Wrapping regexp in cellfun does much the same thing, just slower and more complex.

[Walter Roberson]

This is what I would use.

[the cyclist]

Yes, should definitely swap to this accepting this one! The cellfun is a needless complication in my solution.