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apparently I don't know how to use Map (or Apply or MapThread)

• To: mathgroup at smc.vnet.net
• Subject: [mg77290] apparently I don't know how to use Map (or Apply or MapThread)
• From: dbsearch04 at yahoo.com
• Date: Wed, 6 Jun 2007 07:17:01 -0400 (EDT)

I started with this:

m = {{0.098, 0.951, 0.954}, {0.509, 0.914, 0.487}}

I tried to do this

Table[#[[i, i]], {i, Length[#]}] & /@ m

It does not work, but this works

Diag := Function[x, Table[x[[i, i]], {i, Length[x]}]]; Diag[m]

!@#$%^&*(

Can anyone tell me why? I also tried: Apply, MapThread,
DiagonalMatrix, TakeMatrix, adding () around the pure function...

I know that this is a simple problem. Would Evaluate help?

TIA.

Regards..

• Follow-Ups:
  • Re: apparently I don't know how to use Map (or Apply or MapThread)
    • From: Sseziwa Mukasa <mukasa@jeol.com>