How to extract only part of a file name

I am trying to extract a file but i don´t want to extract it´s entire name. For example:

In

inv_1000061014358_20150424_115235

I only want to extract inv_1000061014358.

Can anyone help?

Thanks!!!!

Answer 1

[dpb]

Presuming the numeric substring isn't the same length always,

ix=strfind(s,'_');  % get the underscore locations
t=s(1:ix(2)-1);     % return the substring up to 2nd underscore

One can also use find to only get the first two locations; would be handy if it also had the ability to return an N th argument instead of just first or last N; then wouldn't have to use the intermediate index vector.

Or, one can use regexp

[Inês Mendes]

Thank you so much!:)

Answer 2

[Guillaume]

In this sort of cases, I would use a regular expression just because it expresses better that you want to extract a portion of the string that conform to a particular pattern.

It's not obvious from the question what that pattern is. Assuming it is: 1 or more alphabetic characters, an underscode, one or more numbers, before another underscore, then:

s = 'inv_1000061014358_20150424_115235';
ss = regexp(s, '^[a-z]+_\d+(?=_)', 'match', 'once')

If regular expressions look too daunting then dpb's answer is the way to go.

[Inês Mendes]

Thanks!Both options work fine :)