how to get the first 3 characters of each element in a cell to another cell

 filename={'CD2.2008052716-17hZCFPF.GY.txt', 'GOM.2008052716-17hZCFPF.GY.txt','GYA.2008052716-17hZCFPF.GY.txt'}
then I want to get a new cell
it would be like {'CD2',"GOM','GYA'};

how to make it

Answer 1

[Jan]

filename = {'CD2.2008052716-17hZCFPF.GY.txt', ...
            'GOM.2008052716-17hZCFPF.GY.txt', ...
            'GYA.2008052716-17hZCFPF.GY.txt'};
P = strtok(filename, '.')

[Roger]

nice

Answer 2

[Azzi Abdelmalek]

out=cellfun(@(x) x{1},regexp(filename,'[^\.]+(?=\.(.+))','match'),'un',0)

[Jan]

Or without cellfun:

regexp(filename,'[^\.]+(?=\.(.+))', 'match', 'once')

Answer 3

[Andrei Bobrov]

In the general case:

filename = {'CZXDD2.2008052716-17hZCFPF.GY.txt', 'GOM.2008052716-17hZCFPF.GY.txt','GY3SAA9.2008052716-17hZCFPF.GY.txt'};

out = regexp(filename,'^\w*(?=\.)','match');
out = [out{:}];