Data update

Task/Substring/OCaml/substring.ml

@@ -0,0 +1,24 @@
+$ ocaml
+# let s = "ABCDEFGH" ;;
+val s : string = "ABCDEFGH"
+
+# let n, m = 2, 3 ;;
+val n : int = 2
+val m : int = 3
+
+# String.sub s n m ;;
+- : string = "CDE"
+
+# String.sub s n (String.length s - n) ;;
+- : string = "CDEFGH"
+
+# String.sub s 0 (String.length s - 1) ;;
+- : string = "ABCDEFG"
+
+# String.sub s (String.index s 'D') m ;;
+- : string = "DEF"
+
+# #load "str.cma";;
+# let n = Str.search_forward (Str.regexp_string "DE") s 0 in
+  String.sub s n m ;;
+- : string = "DEF"