Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2008

[Date Index] [Thread Index] [Author Index]

Search the Archive

Selecting Element from List via Pattern Matching

  • To: mathgroup at smc.vnet.net
  • Subject: [mg89396] Selecting Element from List via Pattern Matching
  • From: immanuel.bloch at googlemail.com
  • Date: Sun, 8 Jun 2008 02:32:39 -0400 (EDT)

Hello,

 I am trying to extract from a Power Series all elements with a
certain exponent, e.g.
let us say I have generated a list via

t = Apply[List, Expand[(Sum[Subscript[a, i], {i, 1, 5}])^3]]

How can I then extract all terms with e.g. a_2^2 in it or any other
exponent?

I have tried something like

Cases[t, Times[_, Power[Subscript[a,2],2]]]

but this somehow only works with the exponent n=1 and no others...

Does anybody know a solution to this pattern matching problem?

Thanks!
Immanuel


  • Prev by Date: Re: Major problem with 6.0.2.1
  • Next by Date: color depth of eps export
  • Previous by thread: Re: Dynamic GUI problem II.
  • Next by thread: Re: Selecting Element from List via Pattern Matching