Data commit

Task/Determine-if-a-string-has-all-the-same-characters/Racket/determine-if-a-string-has-all-the-same-characters.rkt

@@ -0,0 +1,17 @@
+#lang racket
+
+(define (first-non-matching-index l =)
+  (and (not (null? l)) (index-where l (curry (negate =) (car l)))))
+
+(define (report-string-sameness s)
+  (printf "~s (length: ~a): ~a~%"
+          s
+          (string-length s)
+          (cond [(first-non-matching-index (string->list s) char=?)
+                 => (λ (i)
+                      (let ((c (string-ref s i)))
+                        (format "first different character ~s(~a) at position: ~a" c (char->integer c) (add1 i))))]
+                [else "all characters are the same"])))
+
+(module+ test
+  (for-each report-string-sameness '("" "   " "2" "333" ".55" "tttTTT" "4444 444k")))