Why the numbers are not summed?

[crixtiano]

Please, I need help understanding something:

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Command: (setq pt (list 1.0 2.0 3.0))

(1.0 2.0 3.0)

Command: (cddr pt)

(3.0)

 Command: (+ (cddr pt) 100)

; error: bad argument type: numberp: (3.0)

Command: (+ (cddr pt) 100.0)

; error: bad argument type: numberp: (3.0)

=================================================

Why the above code generates an error?

Why the numbers are not summed?

Thank you!

Cristiano

[crixtiano]

Because cdr returns a list and not a number. LOL

😉

[hmsilva]

Hi Cristiano,

cddr will return a list,

change to

(+ (caddr pt) 100.0)

EDIT: too slow...

HTH

Henrique

[devitg]

3 options  

 (setq pt (list 1.0 2.0 3.0))
;;;(1.0 2.0 3.0)


(setq pt+100z ( mapcar '+ pt (list 0 0 100)))

(setq z+100 ( + (last pt) 100))

(setq z++100 ( + (car(cddr pt))))