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Re: what's wrong?!!

  • To: mathgroup at smc.vnet.net
  • Subject: [mg115838] Re: what's wrong?!!
  • From: DrMajorBob <btreat1 at austin.rr.com>
  • Date: Sat, 22 Jan 2011 03:22:36 -0500 (EST)

Cases[A[l1] == A[l2] && i + B[l2] == iP + B[l1], A | B, {0, Infinity},
   Heads -> True]

{A, A, B, B}

Bobby

On Fri, 21 Jan 2011 03:28:37 -0600, olfa <olfa.mraihi at yahoo.fr> wrote:

> On 18 jan, 11:52, "Sjoerd C. de Vries" <sjoerd.c.devr... at gmail.com>
> wrote:
>> The problem lies in the level specification. In the second example you
>> try to match something that is at the top level of the expression. By
>> default level expressions start at 1, but here you need to start at 0.
>> The first expression is And[Equal[...],Equal[...]], but in the second
>> expression you have Equal[...], but Mathematica tries to match with the  
>> .  ..
>> part (level 1 and deeper). The following works:
>>
>> In[236]:= Cases[yP == y + x - z, yP == _, {0, Infinity}]
>>
>> Out[236]= {yP == x + y - z}
>>
>> Cheers -- Sjoerd
>>
>> On Jan 17, 11:40 am,olfa<olfa.mra... at yahoo.fr> wrote:
>>
>>
>>
>> > Hi Mathematica community,
>>
>> > I try to use Case[exp,patt,Infinity]
>>
>> > for the first example it works:
>> > Cases[iP == i + v && kaP == 3^v,  iP == _ | kaP == _,=
>  I=
>> nfinity]
>> > the output is  {iP == i + v, kaP == 3^v}
>>
>> > but not for the second one!!
>> >  Cases[yP == y + x - z, yP == _, Infinity]
>> > the output is  {}
>>
>> > why?!!
>>
>> > Thank you.- Masquer le texte des messages pr=E9c=E9dents -
>>
>> - Afficher le texte des messages pr=E9c=E9dents -
>
> still have problem with Cases for another example:
>
> Cases[A[l1] == A[l2] && i + B[l2] == iP + B[l1], A | B, {0, Infinity}]
>
> returns {} why?!
>


-- 
DrMajorBob at yahoo.com


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