update

Task/Substring/Racket/substring.rkt

@@ -0,0 +1,25 @@
+#lang racket
+
+(define str "abcdefghijklmnopqrstuvwxyz")
+
+(define n 10)
+(define m 2)
+(define start-char #\x)
+(define start-str "xy")
+
+;; starting from n characters in and of m length;
+(substring str n (+ n m)) ; -> "kl"
+
+;; starting from n characters in, up to the end of the string;
+(substring str m) ; -> "klmnopqrstuvwxyz"
+
+;; whole string minus last character;
+(substring str 0 (sub1 (string-length str))) ; -> "abcdefghijklmnopqrstuvwxy"
+
+;; starting from a known character within the string and of m length;
+(substring str (caar (regexp-match-positions (regexp-quote (string start-char))
+                                             str))) ; -> "xyz"
+
+;; starting from a known substring within the string and of m length.
+(substring str (caar (regexp-match-positions (regexp-quote start-str)
+                                             str))) ; -> "xyz"

Task/Substring/Raven/substring.raven

@@ -0,0 +1,26 @@
+define println use $s
+   $s print "\n" print
+
+"0123456789" as $str
+
+$str 3 2 extract println      # at 4th pos get 2 chars
+$str 8 4 extract println      # at 9th pos get 4 chars (when only 1 char available)
+
+
+$str 3  $str length  extract println      # at 4th pos get all chars to end of str
+$str 3  0x7FFFFFFF  extract println      # at 4th pos get all chars to end of str
+
+$str 3 -1 extract println      # at 4th pos get rest of chars but last one
+$str 0 -1 extract println      # all chars but last one
+
+"3" as $matchChr               # starting chr for extraction
+4 as $subLen                   # Nr chars after found starting char
+$str $matchChr split as $l
+"" $l 0 set     $l $matchChr join
+0 $subLen extract println
+
+"345" as $matchChrs            # starting chrs for extraction
+6 as $subLen                   # Nr chars after found starting chars
+$str $matchChrs split as $l
+"" $l 0 set     $l $matchChrs join
+0 $subLen extract println

Task/Substring/Ruby/substring.rb

@@ -1,9 +1,10 @@
 str = 'abcdefgh'
 n = 2
 m = 3
-puts str[n, m]
-puts str[n..-1]
-puts str[0..-2]
-puts str[str.index('d'), m]
-puts str[str.index('de'), m]
-puts str[/a.*d/]
+puts str[n, m]                  #=> cde
+puts str[n..m]                  #=> cd
+puts str[n..-1]                 #=> cdefgh
+puts str[0..-2]                 #=> abcdefg
+puts str[str.index('d'), m]     #=> def
+puts str[str.index('de'), m]    #=> def
+puts str[/a.*d/]                #=> abcd