"rand @_ is like rand 15, which returns an integer between 0 and 14."

Actually, that's incorrect (with respect to rand returning an integer). The first sentence of the rand documentation reads:

"Returns a random fractional number greater than or equal to 0 and less than the value of EXPR."

As an example (which I'll continue to use below): 

$ perl -le '$x = rand 2; print $x'
0.0874574767967786

[download]

I believe, although I can't find any documentation to back it up, that Perl knows the index must be an integer and applies a behind-the-scenes int (or equivalent) to the index. I can use the above rand result directly without getting a warning: 

$ perl -wle '@y = qw{a b c}; print $y[0.0874574767967786]'
a

[download]

Even B::Deparse only reports 0 as the index: 

$ perl -MO=Deparse -e '@y = qw{a b c}; print $y[0.0874574767967786]'
@y = ('a', 'b', 'c');
print $y[0];
-e syntax OK

[download]

I'd be interested if anyone has more information about this (including, but not limited to, if this behaviour is documented).

— Ken

In reply to Re^2: How it works? by kcott
in thread How it works? by monorels

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