string sub ranging - comments by Grey@TMI-2
You can take a substring from a variable ( str ) buy using the substring
operation ( str[n1..n2] ). Positive values are taken from the left and
negative values from the right. If a value is greater than the length of
the string it will be treated as being equal to the length of the string.
If the two values are equal ( str[n1..n1] ) then the character at that
position ( n1 ) is returned. If both values point to positions beyond
the same end of the string the null string ( "" ) is returned. If the
position pointed to by the first value is after the one pointed to by
the second then the null string is also returned.
Examples:
str = "abcdefg"
str[0..0] == "a"
str[0..-1] == "abcdefg"
str[-4..-2] == "def"
str[-7..6] == "abcdefg"
str[3..2] == ""
