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] => {}