--- a/DOCUMENTATION.markdown Tue Jan 17 21:33:28 2017 +0000
+++ b/DOCUMENTATION.markdown Thu Jan 19 17:05:14 2017 +0000
@@ -1403,6 +1403,19 @@
+### `EXTREMA` (function)
+
+ (EXTREMA PREDICATE SEQUENCE)
+
+Return the smallest and largest elements of `sequence` according to `predicate`
+
+ `predicate` should be a strict ordering predicate (e.g. `<`).
+
+ Returns the smallest and largest elements in the sequence as two values,
+ respectively.
+
+
+
### `FREQUENCIES` (function)
(FREQUENCIES SEQUENCE &KEY (TEST 'EQL))--- a/losh.lisp Tue Jan 17 21:33:28 2017 +0000
+++ b/losh.lisp Thu Jan 19 17:05:14 2017 +0000
@@ -1676,6 +1676,23 @@
(sequence (drop-seq n seq))))
+(defun extrema (predicate sequence)
+ "Return the smallest and largest elements of `sequence` according to `predicate`
+
+ `predicate` should be a strict ordering predicate (e.g. `<`).
+
+ Returns the smallest and largest elements in the sequence as two values,
+ respectively.
+
+ "
+ (iterate (with min = (elt sequence 0))
+ (with max = (elt sequence 0))
+ (for el :in-whatever sequence)
+ (when (funcall predicate el min) (setf min el))
+ (when (funcall predicate max el) (setf max el))
+ (finally (return (values min max)))))
+
+
;;;; Debugging & Logging ------------------------------------------------------
(defun pr (&rest args)
"Print `args` readably, separated by spaces and followed by a newline.--- a/package.lisp Tue Jan 17 21:33:28 2017 +0000
+++ b/package.lisp Thu Jan 19 17:05:14 2017 +0000
@@ -241,6 +241,7 @@
(defpackage :losh.sequences
(:documentation "Utilities for operating on sequences.")
(:export
+ :extrema
:prefix-sums
:frequencies
:proportions