how to combine strfind and index in one line？

I tried to run strfind(argument,argument)(1) to return the first hit position, but matlab returns a error. It seems that I need to split the command into two lines？ right？Is there any other way to make it in one line？

Answer 1

[Walter Roberson]

second_last = @(V) V(end-1);
positionLast2nd = second_last(strfind(newname, '_'));

It is possible to do it without the helper function, but it really is not worth doing except to prove that you can, because the code gets obscure.

Answer 2

[Chad Greene]

You could use regexp with the 'once' option. For example, for this string:

str = ['Soldiers! Don''t give yourselves to brutes - men who despise you, enslave you, who '...
   'regiment your lives, tell you what to do, what to think or what to feel! Who drill you,'...
   'diet you, treat you like cattle, use you as cannon fodder.']

Each instance of the word you begins at the following indices:

regexp(str,'you') 
ans =
    22    61    74    92   109   166   176   187   208

If you only want the first instance use the 'once' option:

regexp(str,'you','once')
ans =
    22

[raym]

Hi,Chad.

Thanks a lot.

Dose regexp has other options to retrieve other than the first position?

In fact this is what I really want to do:

newname = 'aasw_43w-f45_rmg-rk_dwfewf_rgrg_v-b';

nich = strfind(newname,''_'');

% find the position of last second  '_':

positionLast2nd = nich(length(strfind(newname,''_''))-1)

=====

I tried to combine these two commands in one line as:

positionLast2nd = strfind(newname,''_'')(length(strfind(newname,''_''))-1)

error appears.

[Stephen23]

+1 nice use of regexp.

Answer 3

[raym]

newname = 'aasw_43w-f45_rmg-rk_dwfewf_rgrg_v-b';
eval('nich = strfind(newname,''_''); nich(length(strfind(newname,''_''))-1)')
% ans then could be used directly.

[Walter Roberson]

We distinctly recommend against using eval. eval() often leads to subtle bugs that show up only sometimes and are hard to find. It is also a big security risk.