MathGroup Archive: April 2012 [00493]

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Distinquishing #'s in nested pure functions

To: mathgroup at smc.vnet.net
Subject: [mg126249] Distinquishing #'s in nested pure functions
From: "Dave Snead" <dsnead6 at charter.net>
Date: Fri, 27 Apr 2012 06:48:11 -0400 (EDT)
Delivered-to: l-mathgroup@mail-archive0.wolfram.com
References: <201204260933.FAA05752@smc.vnet.net>

Hi,

Is there a way to distinguish the #'s in nested pure functions?

As a simple example:

f[x_, y_] := x - y

Select[{1, 2, 3}, (f[#, #] & /@ {-1, -2, -3}) == {3, 4, 5} &]

I want the 1st # to correspond with the outer & (the equal)
and the 2nd # with the inner & (the map)
The answer in this example should by {2}
(of course, the statement as written above does not do the job)

Can Mathematica distinguish these #'s?

Thanks in advance,
Dave Snead

Follow-Ups:
- Re: Distinquishing #'s in nested pure functions
  - From: Murray Eisenberg <murray@math.umass.edu>
- Re: Distinquishing #'s in nested pure functions
  - From: Sseziwa Mukasa <mukasa@gmail.com>

References:
- NonlinearModelFit and Complex Data
  - From: Maria <rouelli@gmail.com>

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