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Re: extract from Reduce

  • To: mathgroup at smc.vnet.net
  • Subject: [mg130356] Re: extract from Reduce
  • From: awnl <awnl at gmx-topmail.de>
  • Date: Thu, 4 Apr 2013 22:30:55 -0400 (EDT)
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  • References: <kjkc5k$7n0$1@smc.vnet.net>

Hi,

> I have a result from the command Reduce that looks like this (as an
> example):
>
> a:= x==3||x==4||x==7
>
> I need to extract the numbers but I can't find a nice way to handle
> the case when there is only one equation, for instance:
>
> a:= x==6
>
> currently I check what the head of the expression is (Head[a]) and
> handle the case Head[a]=Or with a Map[] and the case Head[a]="Equal"
> with a[[2]]. Not very nice, but I guess that there is a neat way to
> do it.
>

There might be more efficient ways to do this, but I think this is clear 
and compact:

Cases[{a}, Equal[x, v_?NumericQ] :> v, Infinity]

hth,

albert



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