[ < ] [ > ]   [ << ] [ Up ] [ >> ]         [Top] [Contents] [Index] [ ? ]

4.1.7.3 Extracting a Subsequence of a List or String

The range expression extracts a specified subsequence from a list or string:

 
expression-1[expression-2..expression-3]

The three expressions are evaluated in order. Expression-1 must return a list or string (the sequence) and the other two expressions must return integers (the low and high indices, respectively); otherwise, E_TYPE is raised. The $ expression can be used in either or both of expression-2 and expression-3 just as before, meaning the length of the value of expression-1.

If the low index is greater than the high index, then the empty string or list is returned, depending on whether the sequence is a string or a list. Otherwise, both indices must be between 1 and the length of the sequence; E_RANGE is raised if they are not. A new list or string is returned that contains just the elements of the sequence with indices between the low and high bounds.

 
"foobar"[2..$]                       =>  "oobar"
"foobar"[3..3]                       =>  "o"
"foobar"[17..12]                     =>  ""
{"one", "two", "three"}[$ - 1..$]    =>  {"two", "three"}
{"one", "two", "three"}[3..3]        =>  {"three"}
{"one", "two", "three"}[17..12]      =>  {}



This document was generated on September, 30 2008 using texi2html