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Re: Help with concatenating a list with &&

  • To: mathgroup at smc.vnet.net
  • Subject: [mg102217] Re: [mg102153] Help with concatenating a list with &&
  • From: Tomas Garza <tgarza10 at msn.com>
  • Date: Sat, 1 Aug 2009 04:03:01 -0400 (EDT)
  • References: <200907310952.FAA19208@smc.vnet.net>

Hello, Jane:



Not being an expert, I find it very useful to peruse the on-line documentation center - when in doubt.

I found that BooleanConvert may be used to answer your query



In[1]:=  ls={ex1,ex2,ex3,ex4}
Out[1]=  {ex1,ex2,ex3,ex4}


In[2]:=  BooleanConvert[Equivalent[Sequence@@ls]]
Out[2]=  (ex1&&ex2&&ex3&&ex4)||(!ex1&&!ex2&&!ex3&&!ex4)



 Taking the first part of the output will give what you are after:


In[3]:= %[[1]]
Out[3]= ex1&&ex2&&ex3&&ex4



Cheers,

Tomas



> Date: Fri, 31 Jul 2009 05:52:48 -0400
> From: janemkiwi at gmail.com
> Subject: [mg102153] Help with concatenating a list with &&
> To: mathgroup at smc.vnet.net
>
> Can anyone help me make better use of mathematica's built in commands?
>
> My problem is to take the list of expressions ls:
>
> ls={ex1, ex2, ex3, ex4}
>
> and connect them to obtain
>
> ex1 && ex2 && ex3 && ex4
>
>
> I thought I should be able to use
>
> && @@ ls
>
> or equivalently Apply[&&, ls]
>
> However this fails. I ended up using the very awkward
>
> conditions = ls[[1]] && ls[[2]]
> Do[conds = conds && ls[[i]], {i, 3, Length[ls]}]
>
> which works but feels like just bludgeoning the problem
>
> Does anyone know of a more elegant way to work this?
>
> Thanks,
> Jane.
>


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