array subscript manipulation

[Jinsong Zhao]

Hi there,

I have an array:

(defvar x (make-array '(5 5) :initial-contents '((1 1 1 1 1)
(2 2 2 2 2)
(3 3 3 3 3)
(4 4 4 4 4)
(5 5 5 5 5))))
Is there a easy way to access or get whole column? For row, I can use
:displaced-to.

Another question, is there a easy way to get x[2, 2:4]?

Thanks in advance.

Best wishes,
Jinsong

[Marco Antoniotti]

On Thursday, April 17, 2014 6:34:49 AM UTC+2, Jinsong Zhao wrote:
> Hi there,
> I have an array:
>
> (defvar x (make-array '(5 5) :initial-contents '((1 1 1 1 1)
> (2 2 2 2 2)
> (3 3 3 3 3)
> (4 4 4 4 4)
> (5 5 5 5 5))))
>
> Is there a easy way to access or get whole column? For row, I can use
> :displaced-to.

No. There is no way to access a "column" unless you copy. Arrays are stored in row major form.

> Another question, is there a easy way to get x[2, 2:4]?

Not directly in the standard. There are libraries and bits and pieces of code to do that.

I should have something laying around. Drop me a line in private...

Cheers
--
MA