Re: Tally

• To: mathgroup at smc.vnet.net
• Subject: [mg86925] Re: Tally
• From: Michael Weyrauch <michael.weyrauch at gmx.de>
• Date: Wed, 26 Mar 2008 04:54:45 -0500 (EST)

```Hello,

I dont't think there is anything wrong with your code, but I know that
under certain conditions Tally does not work properly.

I postet a similar problem re Tally last November to Wolfram support,
and I got the answer that Tally is not always working correctly.

I suggest you write your own Tally function, e.g. using Sow and Reap.
This works fast and perfect in my situations.

Michael Weyrauch

Armen Kocharyan schrieb:
> Dear Group,
>
> I'm trying the following:
>
>
> *Dlist = {{{0,1},{0,1}},{{1,0},{1,0}},{{1,0},{0,1}},{{0,1},{1,0}}};*
>
> *Tally[Dlist,(#1=== #2) \[Or] *
>
> *            (#1[[1]][[1]]=== #2[[1]][[2]] \[And] *
>
> *             #1[[1]][[2]]=== #2[[1]][[1]] \[And] *
>
> *             #1[[2]][[1]]=== #2[[2]][[2]] \[And] *
>
> *             #1[[2]][[2]]=== #2[[2]][[1]] )&]*
>
>
>
> The output is:
>
> *{{{{0,1},{0,1}},1},{{{1,0},{1,0}},1},{{{1,0},{0,1}},2}}*
>
>
> *{{{{0,1},{0,1}},2},{{{1,0},{0,1}},2}}*
>
>
>
> If I remove the last member from DList
>
> *Dlist = {{{0,1},{0,1}},{{1,0},{1,0}},{{1,0},{0,1}}};*
>
> then I got a correct answer
>
> *{{{{0,1},{0,1}},2},{{{1,0},{0,1}},1}}.*
>
>
>
> Is anything wrong with my original code?
>
>
>
> Best regards,
>
> Armen
>
>

```

• Prev by Date: Another stylesheet question
• Next by Date: Re: Mathlink: How do I pass arbitrary data from Mathematica to C?