Re: Span Set nasty bug
- To: mathgroup at smc.vnet.net
- Subject: [mg123855] Re: Span Set nasty bug
- From: roby <roby.nowak at gmail.com>
- Date: Fri, 23 Dec 2011 07:13:35 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <201112161054.FAA07002@smc.vnet.net> <jcut4k$dgi$1@smc.vnet.net>
> Roby, are you aware that expr[[0]] gives access to the head? yes, this is clear to me. But if you look carful at my post then you will see that I do not access the element with the array index 0 (the Head). > I think if you do not want to assign, do not do it. again look carful at my post I don't want and I do not assign to element [[1,1]], the assignment just happens by failure! > (* it is somewhat unfortunate that the following does not issue a message *) > t[[1 ;; 0, 1]] ... perhaps right perhaps wrong, depends on the exact definition of Span[ ] wich in turn should depend on what is recognized as suitable. look at my reply to shizu there I have explained a reasonable application. As the Mathematica behavior now is, I of course must prevent empty Span[ ] I would prefer a defined behavoiur similar as e.g. for Range[1,0] which returns an empty List. One of the principles of Mathematica is elegant functional programming which e.g. avoids thigs like loops etc., one of the helpful features in this connection is Span[ ]. As explained I am looking for a construct that assigns a variable number of elements that means even 0, 1 or any other random number provided as a variable. This works perfekt for Matrices < 15x15, pleeeeease, pleeeease fix it for bigger ones. By the way I have reported this to the Wolfram support. The first answer was that the behaviour is "unexpected" and that the issue is forwarded to the developers. As I had the pleasure to meet you at the Mathematica 2011 Conference in Vienna I would not be too much surpised if the isssu would be forwarded to you ;) Cheers Robert
- References:
- Span Set nasty bug
- From: roby <roby.nowak@gmail.com>
- Span Set nasty bug