Re: First nonzero in list
- To: mathgroup at smc.vnet.net
- Subject: [mg110853] Re: First nonzero in list
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Thu, 8 Jul 2010 07:41:23 -0400 (EDT)
th = {227, 342, 527, 0, 670, 730, 703, 0, 0, 649, 687, 614, 570, 501,
462, 402, 325, 254, 189, 99, 81, 36, 9, 8, 3, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
th /. {a___, 0 ..} :> {a} // Length
25
th /. {a___, 0 ..} :> Length[{a}]
25
Bob Hanlon
---- "S. B. Gray" <stevebg at ROADRUNNER.COM> wrote:
=============
I have lists such as
th = {227, 342, 527, 0, 670, 730, 703, 0, 0, 649, 687, 614, 570, 501,
462, 402, 325, 254, 189, 99, 81, 36, 9, 8, 3, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
and I want to find the position of the last nonzero element (e.g. 3 at
position 25). Trivial, but some poking around did not reveal a neat way.
Anyone? Thank you.
Steve Gray