list c = list a - list b?

I know there has to be a simple way to subtract the contents of one list from another. Any help?

 

any practical sample that i can take a look - to test.?

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from another. Any help?

 

Responding to keyword "simple", and a fuzzy understanding what you mean
"contents of one list from another" ...

(setq
list1 '(1 2 3 4 5)
list2 '(2 3 4)
)

(vl-remove-if
'(lambda (x) (member x list2))
list1
)

returns (1 5)

I know there has to be a simple way to subtract the contents of one list from
another. Any help?

 

That's it. Thanks.

 

Hi michael puckett , how about this below I would "(- list1 list2)"

_$ (setq list1 '(1.9 2.8 3.7 4.8 5.7))

(1.9 2.8 3.7 4.8 5.7)

_$ (setq list2 '(1.1 2.2 3.3 4.1 5.5))

(1.1 2.2 3.3 4.1 5.5)

 

_$ (mapcar '- list1 list2)
(0.8 0.6 0.4 0.7 0.2)


--
R. Robert Bell


Hi michael puckett , how about this below I would "(- list1 list2)"

_$ (setq list1 '(1.9 2.8 3.7 4.8 5.7))

(1.9 2.8 3.7 4.8 5.7)

_$ (setq list2 '(1.1 2.2 3.3 4.1 5.5))

(1.1 2.2 3.3 4.1 5.5)

 

Perfect ! ,thanks Bell

 

Or, alternatively,

(setq list_c nil)
(foreach el list_a
(or (member el list_b)(setq list_c (cons el list_c)))
)

 

?????????????????????

_ (setq list_a '(1.9 2.8 3.7 4.8 5.7))
(1.9 2.8 3.7 4.8 5.7)
_$ (setq list_b '(1.1 2.2 3.3 4.1 5.5))
(1.1 2.2 3.3 4.1 5.5)
_$ (setq list_c nil)
nil
_$ (foreach el list_a
(or (member el list_b)(setq list_c (cons el list_c))))
T

 

the expression itself returns T (that's the return value of or) but look at the value of list_c.