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Re: Is there any difference between `equal' and `string=' for strings?
From: |
Jean Louis |
Subject: |
Re: Is there any difference between `equal' and `string=' for strings? |
Date: |
Sat, 21 Aug 2021 12:04:08 +0300 |
User-agent: |
Mutt/2.0.7+183 (3d24855) (2021-05-28) |
* Emanuel Berg via Users list for the GNU Emacs text editor
<help-gnu-emacs@gnu.org> [2021-08-20 09:25]:
> Jean Louis wrote:
>
> > How I understand it, it is good also for comparison of
> > symbols as strings.
> >
> > (setq s1 "Jane") -> "Jane"
> > (setq s2 "Jane") -> "Jane"
> > (setq s3 "Doe") -> "Doe"
> >
> > Then this is how I understand the intended purpose:
> >
> > (string= s1 s2) -> t
> > (string= s1 s3) -> nil
>
> Uhm, but in that case, s1, s2, and s3 are evaluated to their
> string values, so at the time of `string=', that's
>
> (string= "Jane" "Jane") ; t
> (string= "Jane" "Doe" ) ; nil
Yes, that is what I meant. It is good to compare symbols which are
possibly strings if they are equal to each other.
(setq s1 1) ⇒ 1
(setq s2 "1") ⇒ "1"
Which is also good to show the error if one of symbols is not string:
(string= s1 s2) eval: Wrong type argument: stringp, 1
> > And of course you are free to compare empty symbols:
> >
> > (string= 'hi 'hi) -> t
>
> With symbols their "print names" are used, you can get that
> with
>
> (symbol-name 'hi) ; "hi"
>
> So that's virtually (string= "hi" "hi") only here it is done
> _by_ and not before string= (as 'hi does not evaluate to the
> string "hi", for example).
That I don't understand, what I know is that `string=' will evaluate
symbols as strings and compare them, interesting is it will accept
`nil' as value:
(setq s1 "1") ⇒ "1"
(setq s2 "1") ⇒ "1"
(string= s1 s2) ⇒ t
(setq s1 "1") ⇒ "1"
(setq s2 nil) ⇒ nil
(string= s1 s2) ⇒ nil
--
Jean
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- Re: Is there any difference between `equal' and `string=' for strings?, (continued)
- Re: Is there any difference between `equal' and `string=' for strings?, Emanuel Berg, 2021/08/19
- Re: Is there any difference between `equal' and `string=' for strings?, Jean Louis, 2021/08/20
- Re: Is there any difference between `equal' and `string=' for strings?, Emanuel Berg, 2021/08/20
- Re: Is there any difference between `equal' and `string=' for strings?, Emanuel Berg, 2021/08/20
- Re: Is there any difference between `equal' and `string=' for strings?, Emanuel Berg, 2021/08/20
- Re: Is there any difference between `equal' and `string=' for strings?, Emanuel Berg, 2021/08/20
- Re: Is there any difference between `equal' and `string=' for strings?, Emanuel Berg, 2021/08/20
- Re: Is there any difference between `equal' and `string=' for strings?, Emanuel Berg, 2021/08/20
- Re: Is there any difference between `equal' and `string=' for strings?, Jean Louis, 2021/08/21
- Re: Is there any difference between `equal' and `string=' for strings?, Emanuel Berg, 2021/08/21
- Re: Is there any difference between `equal' and `string=' for strings?,
Jean Louis <=
- Re: Is there any difference between `equal' and `string=' for strings?, Emanuel Berg, 2021/08/21
- Re: Is there any difference between `equal' and `string=' for strings?, Marcin Borkowski, 2021/08/24