Efficient splitting of strings

I have a cell array of strings which I would like to split into sub-arrays as follows:

Suppose a date-time cell array reads as:

 inputArray = 

    '20150316 07:20:39:380941'
    '20150317 07:20:39:380941'
    '20150318 07:20:39:380941'
    '20150319 07:20:39:380941'

I would like the output to be

outputArray = 

    '20150316'
    '20150317'
    '20150318'
    '20150319'

Currently I am doing it by

 outputArray = cellfun(@(x) x(1:8),inputArray,'uni',false);

which works just fine, however for inputArray into the millions of elements, this process is slow.

Is there a more efficient method which can perform the above? I know for sure that the structure of the strings in the array is fixed (i.e. the string length is always 24 and the first 8 elements are YYYYMMDD).

Answer 1

[KSSV]

You can read all the strings into a character matrices and extract what you want. Example:

k = ['20150316 07:20:39:380941'
    '20150317 07:20:39:380941'
    '20150318 07:20:39:380941'
    '20150319 07:20:39:380941'];

k(:,1:9)

Have you tried this?

[Hamad Alsayed]

That is perfect, Siva. Thank you. Even after "cellstr"-ing the answer back, execution time is cut by more than a half. Thanks again! Hamad.