Re: Bug with Sequence
- To: mathgroup at smc.vnet.net
- Subject: [mg104617] Re: [mg104568] Bug with Sequence
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Thu, 5 Nov 2009 03:48:16 -0500 (EST)
- Reply-to: hanlonr at cox.net
As stated in the documentation for Sequence:
"Assignment and replacement functions have attribute SequenceHold."
t = {1, 2, 3}; j = 0;
While[++j < 4, t[[1]] = Sequence[]; Print[t = ReleaseHold[t]]]
{2,3}
{3}
{}
Bob Hanlon
---- dh <dh at metrohm.com> wrote:
=============
Hello,
has anybody an explanation for the behavior of "Sequence"? I think it is
an ugly bug.
Consider the following that shoud succesively shorten the list t:
t = {1, 2, 3}; j = 0;
While[ ++j < 4, t[[1]] = Sequence[]; Print[t]]
this returns: {2,3} three times.Dropping of the first element only seems
to work once.
If you say Information[t] you get:
t={Sequence[],2,3}
Daniel