* Indexing a vector
@ 2008-09-10 14:53 Nordlöw
2008-09-10 15:53 ` Drew Adams
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Nordlöw @ 2008-09-10 14:53 UTC (permalink / raw)
To: help-gnu-emacs
How do index an element in a vector? nth() works only for lists.
:(... 0 '[1 2])
Why on earth isn't such a basic operator compatible with both lists
and vectors (sequences)?
/Nordlöw
^ permalink raw reply [flat|nested] 4+ messages in thread* RE: Indexing a vector
2008-09-10 14:53 Indexing a vector Nordlöw
@ 2008-09-10 15:53 ` Drew Adams
2008-09-10 15:57 ` Juanma Barranquero
2008-09-10 16:52 ` Ted Zlatanov
2 siblings, 0 replies; 4+ messages in thread
From: Drew Adams @ 2008-09-10 15:53 UTC (permalink / raw)
To: 'Nordlöw', help-gnu-emacs
> How do index an element in a vector? nth() works only for lists.
>
> :(... 0 '[1 2])
>
> Why on earth isn't such a basic operator compatible with both lists
> and vectors (sequences)?
`elt'
C-h i, choose Elisp manual, g Sequence Functions
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Indexing a vector
2008-09-10 14:53 Indexing a vector Nordlöw
2008-09-10 15:53 ` Drew Adams
@ 2008-09-10 15:57 ` Juanma Barranquero
2008-09-10 16:52 ` Ted Zlatanov
2 siblings, 0 replies; 4+ messages in thread
From: Juanma Barranquero @ 2008-09-10 15:57 UTC (permalink / raw)
To: Nordlöw; +Cc: help-gnu-emacs
On Wed, Sep 10, 2008 at 16:53, Nordlöw <per.nordlow@gmail.com> wrote:
> How do index an element in a vector?
(aref [a b c d] 2) => c
> nth() works only for lists.
Yes, `nth' is a list operation.
> Why on earth isn't such a basic operator compatible with both lists
> and vectors (sequences)?
Because it is a list operation. For the generic sequence operator, try `elt':
(elt '(a b c d) 2) => c
(elt [a b c d] 2) => c
(elt "abcd" 2) => 99
Juanma
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Indexing a vector
2008-09-10 14:53 Indexing a vector Nordlöw
2008-09-10 15:53 ` Drew Adams
2008-09-10 15:57 ` Juanma Barranquero
@ 2008-09-10 16:52 ` Ted Zlatanov
2 siblings, 0 replies; 4+ messages in thread
From: Ted Zlatanov @ 2008-09-10 16:52 UTC (permalink / raw)
To: help-gnu-emacs
On Wed, 10 Sep 2008 07:53:04 -0700 (PDT) Nordlöw <per.nordlow@gmail.com> wrote:
N> How do index an element in a vector? nth() works only for lists.
N> :(... 0 '[1 2])
N> Why on earth isn't such a basic operator compatible with both lists
N> and vectors (sequences)?
The Emacs Lisp manual (chapter 6) covers this. A vector is an array
which is a sequence, but not a list (so you can use the `elt' function
in addition to `aref' to look up elements). `nth' works only on lists.
Ted
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2008-09-10 14:53 Indexing a vector Nordlöw
2008-09-10 15:53 ` Drew Adams
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