--> What is the index of the first element of an array in Perl?
$[ The index of the first element in an array, and of the fir
character in a substring. Default is 0, but you could
theoretically set it to 1 to make Perl behave more like aw
Fortran) when subscripting and when evaluating the index()
substr() functions. (Mnemonic: [ begins subscripts.)
As of release 5 of Perl, assignment to $[ is treated as a
compiler directive, and cannot influence the behavior of a
other file. (That's why you can only assign compile-time
constants to it.) Its use is highly discouraged.
Note that, unlike other compile-time directives (such as
strict), assignment to $[ can be seen from outer lexical s
in the same file. However, you can use local() on it to st
bound its value to a lexical block.