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MathGroup Archive 2001

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Re: find argument of function inside long result?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg31347] Re: [mg31313] find argument of function inside long result?
  • From: "Johannes Ludsteck" <johannes.ludsteck at wiwi.uni-regensburg.de>
  • Date: Tue, 30 Oct 2001 04:35:30 -0500 (EST)
  • Organization: Universitaet Regensburg
  • Sender: owner-wri-mathgroup at wolfram.com

Dear jose,
use pattern matching functions
Here is an example. I try to extract all 
arguments of Sqrt[_] from an expression. This 
defines the expression:

expr=Sqrt[a] Sin[Sqrt[Sqrt[d]+e] 5+c]

This extracts all root subexpressions and returns 
a list of them.
temp=Cases[expr,Sqrt[__],Infinity]

Only one additional step extracts the arguments 
from the Sqrt[_] terms:

Map[Cases[#,_]&,temp]

Of course, you can combine both steps
Map[Cases[#,_]&,Cases[expr,Sqrt[__],Infinity]]

Note that argument Infinity is important if you 
want to get all Sqrt terms.

Best regards,
	Johannes

On 27 Oct 2001, at 1:08, jose flanigan wrote:

> I have a very long symbolic result that has several sqrt functions. I
> would like to extract the arguments of each of the sqrt's.
> 
> How can I do this? The expression is too complicated to try and read it off.
> 
> thanks.
> 



<><><><><><><><><><><><><><><><><><>
Johannes Ludsteck
Institut fuer Volkswirtschaftslehre
Lehrstuhl Prof. Dr. Moeller
Universitaet Regensburg
Universitaetsstrasse 31
93053 Regensburg
Tel +49/0941/943-2741


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