zl:1 - FTP

435 rem
is empty and no :initial-value is specified, then function is called with zero
arguments, and reduce returns whatever the function returns. (This is the
only case where function is called with other than two arguments.)
sequence can be either a list or a vector (one-dimensional array). Note that
nil is considered to be a sequence, of length zero.
For example:
(reduce #'+ '(1 2 3 4» => 19
(reduce #'- '(1 234) :fram-end t) => -2
(reduce #'+ '(» => 9
(reduce #'+ #(1 1 1 1 1) :start 2 :end 5) => 3
(reduce #'list '(1 2 3 4» => «(1 2) 3) 4)
(reduce #'list '(1 234) :initial-value 'faa :fram-end t) =>
(1 (2 (3 (4 FDD»»
For a table of related items: See the section "Mapping Sequences" in Symbolics
Common Lisp: Language Concepts.
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rem number divisor Function
rem divides number by divisor, truncating the quotient toward zero, and
returns the remainder. This is the same as the second value of (truncate
number divisor). If q and r denote, respectively, the quotient and
remainder, then: q III divisor + r = number.
The arguments can be rational or floating-point numbers. The returned
value, r is rational if both arguments are rational; it is floating-point if either
argument is floating-point.
Examples:
(rem 3 2) => 1
(rem 3 -2) => 1
(rem -3 2) => -1
(rem -3 -2) => -1
(rem 4 2) => 9
(rem 3.8 2) => 1.8
(rem -3.8 2) => -1.8
(rem 19/5 2) => 9/5
The following functions are synonyms of rem: