Groups > comp.soft-sys.math.mathematica > #16676

Re: Mapping tag-value lists to a third

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From	carlos.felippa%colorado.edu@gtempaccount.com
Newsgroups	comp.soft-sys.math.mathematica
Subject	Re: Mapping tag-value lists to a third
Date	Thu, 20 Mar 2014 09:28:06 +0000 (UTC)
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Thanks to all who replied.  For now I have implemented it as

tagval=If [$VersionNumber>=5.1,Pick[val,tag,1],val*tag/. 0:>Sequence[]];

For big lists, Pick is slightly faster. Eg, for 10^7 length, on a MacPro:

     Pick 1.45 sec    Sequence: 1.72 sec

The reason for $VersionNumber is that Pick appeared in 5.1. Some
users of my Mathematica codes are colleagues living overseas who run
version 4 on old computers.

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Mapping tag-value lists to a third carlos.felippa%colorado.edu@gtempaccount.com - 2014-03-17 06:27 +0000
  Re: Mapping tag-value lists to a third carlos.felippa%colorado.edu@gtempaccount.com - 2014-03-20 09:28 +0000

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