On Wed, 28 Nov 2001, Ian Phillipps wrote:
> On Tue, 27 Nov 2001 at 11:31:39 -0600, Andy Bach wrote:
> > Okay, would the maths folk like to offer a helpful explanation?
> > ---------- Forwarded message ----------
> > How do I select a random line from a file?
>
> See also
> http://groups.google.com/groups?threadm=xn9zo7tvb5h.fsf%40owl.doc.ic.ac.uk
Tada! Got it, finally - though my denseness partially hinged on
misreading the "significant advantage in space over reading the whole
file" addendum - you still read the whole file, but only have one line at
at time (or however its handled) in mem. I was thinking it somehow
short-circuited the while once it succeeded (being < 1).
Thanks much. I thought there might be related technique for getting a
rand element from an array, but we know the array length so ... this
(from above) did help w/ my getting all the elements in a random order, i.e.:
while ( @arr ) {
$pos = rand($#arr);
$val = splice @arr, $pos, 1;
print "is: $val\n";
}
Such fun!
a
Andy Bach, Sys. Mangler
Internet: [EMAIL PROTECTED] VOICE: (608) 264-5178 ex 5738, FAX 264-510
"Murphy's Law, that brash proletarian restatement of Godel's Theorem ..."
-- Thomas Pynchon, "Gravity's Rainbow"
