Re: Help with elisp

[Kevin Rodgers]

Tom Capey wrote:

> * David Chadd <d.chadd@uea.ac.uk> writes:
> > Having found the string of values (CAO-C Alb2 Hyd) with a regexp
> > search, I simple-mindedly thought I would be able to do something like
> >
> >  (setq wits (split-string (match-string 1)))
> >
> > This does indeed make a list --- (listp wits) returns T --- but the
> > lists don't behave as I would expect.  For instance, they don't
> > respond correctly to (set-difference), (intersection) etc.  And for
> > reasons I can guess at, but don't know enough to do anything about,
> > the lists are in the form ("CAO-C" "Alb2" "Hyd") rather than (CAO-C
> > Alb2 Hyd).
>
>   change the test in the set functions from `eq':
>
> (setq a (list "CAO-C" "Alb2" "Hyd")
>       b (list "CAO-C" "Alb2" "Hyd" "foo"))
>
> (intersection a b :test 'string-equal)
> => ("Hyd" "Alb2" "CAO-C")
>
> (set-difference b a :test 'string-equal)
> => ("foo")
>
> (set-difference a b :test 'string-equal)
> => nil

Or create a list of symbols (which can be compared with `eq')

instead of strings (which can't):

(setq wits (mapcar 'intern (split-string (match-string 1))))

--
Kevin Rodgers