Nyquist / XLISP 2.0 -
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cdar, cddr
Type: |
- |
function (subr) |
Source: |
- |
xllist.c |
Syntax
- (cdar expr)
(cddr expr)
- expr - a list or list expression
returns - the result of the last cdr
function
Description
The 'cdar' and 'cddr' functions go through the list expression and perform a
sequence of car or
cdr operations. The sequence of
operations is performed from right to left. So 'cdar' does a
car on the expression, followed by a
cdr. If at any point the list is
NIL, then NIL is returned.
If at any point a car operation is
performed on an atom [as opposed to a list] an error is signalled:
error: bad argument
Examples
(setq mylist '((1A 1B) (2A 2B) (3A 3B)))
(caar mylist) => 1A
(cadr mylist) => (2A 2B)
(cdar mylist) => (1B)
(cddr mylist) => ((3A 3B))
(cdar 'a) => error: bad argument
(cdar nil) => NIL
Note: The 'c...r' functions are part of the
historical Lisp functions. You may find it easier to work with the modern
lisp functions like nth and
nthcdr.
See also:
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Nyquist / XLISP 2.0 -
Contents |
Tutorials |
Examples |
Reference