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Task/Binary-strings/Racket/binary-strings.rkt

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+#lang racket
+
+;; Byte strings can be created either by a function (b1)
+;; or as a literal string (b2). No operation is needed for
+;; destruction due to garbage collection.
+
+(define b1 (make-bytes 5 65))  ; b1 -> #"AAAAA"
+(define b2 #"BBBBB")           ; b2 -> #"BBBBB"
+
+;; String assignment. Note that b2 cannot be
+;; mutated since literal byte strings are immutable.
+
+(bytes-set! b1 0 66)           ; b1 -> #"BAAAA"
+
+;; Comparison. Less than & greater than are
+;; lexicographic comparison.
+
+(bytes=? b1 b2)                ; -> #f
+(bytes<? b1 b2)                ; -> #t
+(bytes>? b1 b2)                ; -> #f
+
+;; Byte strings can be cloned by copying to a
+;; new one or by overwriting an existing one.
+
+(define b3 (bytes-copy b1))    ; b3 -> #"BAAAA"
+(bytes-copy! b1 0 b2)          ; b1 -> #"BBBBB"
+
+;; Byte strings can be appended to one another. A
+;; single byte is appended as a length 1 string.
+
+(bytes-append b1 b2)           ; -> #"BBBBBBBBBB"
+(bytes-append b3 #"B")         ; -> #"BAAAAB"
+
+;; Substring
+
+(subbytes b3 0)                ; -> #"BAAAA"
+(subbytes b3 0 2)              ; -> #"BA"
+
+;; Regular expressions can be used to do replacements
+;; in a byte string (or ordinary strings)
+
+(regexp-replace #"B" b1 #"A")  ; -> #"ABBBB" (only the first one)
+(regexp-replace* #"B" b1 #"A") ; -> #"AAAAA"
+
+;; Joining strings
+
+(bytes-join (list b2 b3) #" ") ; -> #"BBBBB BAAAA"