count, count-if, count-if-not
count, count-if, count-if-not Function
Syntax:
count item sequence &key from-end start end key test test-not → n
count-if predicate sequence &key from-end start end key → n
count-if-not predicate sequence &key from-end start end key → n
Arguments and Values:
item—an object.
sequence—a proper sequence.
predicate—a designator for a function of one argument that returns a generalized boolean. from-end—a generalized boolean. The default is false.
test—a designator for a function of two arguments that returns a generalized boolean. test-not—a designator for a function of two arguments that returns a generalized boolean.
start, end—bounding index designators of sequence. The defaults for start and end are 0 and nil, respectively.
key—a designator for a function of one argument, or nil.
n—a non-negative integer less than or equal to the length of sequence.
Description:
count, count-if, and count-if-not count and return the number of elements in the sequence bounded by start and end that satisfy the test.
The from-end has no direct effect on the result. However, if from-end is true, the elements of sequence will be supplied as arguments to the test, test-not, and key in reverse order, which may change the side-effects, if any, of those functions.
Examples:
(count #\a "how many A’s are there in here?") → 2
(count-if-not #’oddp ’((1) (2) (3) (4)) :key #’car) → 2
(count-if #’upper-case-p "The Crying of Lot 49" :start 4) → 2
Exceptional Situations:
Should be prepared to signal an error of type type-error if sequence is not a proper sequence.
See Also:
Section 17.2 (Rules about Test Functions), Section 3.6 (Traversal Rules and Side Effects)
Notes:
The :test-not argument is deprecated.
The function count-if-not is deprecated.
Expanded Reference: count, count-if, count-if-not
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(count, count-if, count-if-not )