Re: Finding a function within an arbitrary expression

• To: mathgroup at smc.vnet.net
• Subject: [mg131360] Re: Finding a function within an arbitrary expression
• From: Alexei Boulbitch <Alexei.Boulbitch at iee.lu>
• Date: Mon, 1 Jul 2013 05:49:18 -0400 (EDT)
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```I am trying to figure out what that pattern is for the following. The difficulty here is that I can think textually, but not in Mathematica patterns.

I am looking for a function u[1,0] within a list of expressions. The function might not be defined yet. For example, a list of expressions might be:

{3*u[1,0], u[0,0]/10., 1/u[1,0], ...}

I want to find all the expressions that have the function u[1,0] in it. There is certainly a way to do this "textually". How would one do this with patterns? Is it possible? Thank you.

Hi, Anthony,

Try this:

Select[{3*u[1, 0], u[0, 0]/10., 1/u[1, 0]}, MemberQ[#, u[1, 0]] &]

{3 u[1, 0], 1/u[1, 0]}

Have fun, Alexei

Alexei BOULBITCH, Dr., habil.
IEE S.A.
ZAE Weiergewan,
11, rue Edmond Reuter,
L-5326 Contern, LUXEMBOURG

Office phone :  +352-2454-2566
Office fax:       +352-2454-3566
mobile phone:  +49 151 52 40 66 44

e-mail: alexei.boulbitch at iee.lu

```

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