topic Re: Compare value with list in Visual LISP, AutoLISP and General Customization Forum

Compare value with list

carlos_m_gil_p — Fri, 21 May 2021 04:41:21 GMT

Hello boys how are you.

I wanted to ask you, how can I compare a numerical value with a list and know if they are the same or not.

I have two variables.

(setq val 0.0)

(setq lst '(-0.23297 -0.23297 1.0 0.05 4))

val contains the value to compare. This value can be any.

lst contains a list of values, this list can have one or more values.

I need it to return T if all the values of the variable lst are equal to the value of the variable val.

Beforehand thank you very much.

ВeekeeCZ — Fri, 21 May 2021 06:33:26 GMT

Try

(apply '= (cons val lst))

carlos_m_gil_p — Sun, 23 May 2021 22:35:33 GMT

Hello brother, thanks for your help, it worked very well.

Greetings.

john.uhden — Sun, 23 May 2021 23:52:41 GMT

I wrote this earlier today, but something snapped... gone.

Real numbers are not as exact as one might think.

If you are looking for matches that are close enough then

(setq fuzz 0.00001) ;; or whatever you like, then

(vl-every '(lambda (x)(equal val x fuzz)) lst)

carlos_m_gil_p — Mon, 24 May 2021 01:03:53 GMT

Hello Brother how are you.
I tried your option and it works very well for me.
I think the more exact the better.
I don't know which is better.

ronjonp — Mon, 24 May 2021 03:57:38 GMT

IMO, use your acceptable tolerance when comparing real numbers.

carlos_m_gil_p — Mon, 24 May 2021 05:09:26 GMT

Hello guys, thanks for all the opinions and help, I will take them into account.
Greetings.