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Re: Pure function in a pure function (again)

• To: mathgroup at smc.vnet.net
• Subject: [mg69805] Re: Pure function in a pure function (again)
• From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
• Date: Sat, 23 Sep 2006 06:14:52 -0400 (EDT)
• Organization: The Open University, Milton Keynes, UK
• References: <ef2tl4$mn4$1@smc.vnet.net>

Skirmantas Janusonis wrote:
> Hello,
> 
> I've already asked this question, but I thought there was a better way to state it. If Dat is a 2D-table, the following picks out the rows whose first element is 1,2 or 3 and adds up their the second elements:
> 
> f[x_] := Plus @@ Column[Select[Dat, #[[1]] == x &], 2]
> f /@ Range[3]
> 
> Instead of f/@Range[3], I'd like to use a second pure function, something like this:
> 
> Map[Plus @@ Column[Select[Dat, #1[[1]] == #2 &], 2]&,Range[3]]
--------------------------------------------** What this variable is 
supposed to be and from where it is supposed to get any value?

Jean-Marc