Re: Mapping tag-value lists to a third
- To: mathgroup at smc.vnet.net
- Subject: [mg132444] Re: Mapping tag-value lists to a third
- From: Francisco Gutierrez <fgutiers2002 at yahoo.com>
- Date: Tue, 18 Mar 2014 01:27:44 -0400 (EDT)
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- Reply-to: Francisco Gutierrez <fgutiers2002 at yahoo.com>
What about Extract[val, Position[tag, 1]]?
Francisco
On Monday, March 17, 2014 1:33 AM, "carlos.felippa%colorado.edu at gtempaccount.com" <carlos.felippa%colorado.edu at gtempaccount.com> wrote:
Hi,
I have 2 lists of equal length such as
tag={0, 1, 0, 0, 0, 1, 0, 1}; val={f1,f2,f3,f4,f5,f6,f7,f8}
and want to produce a third:
tagval={f2,f6,f8}
with length Count[tag,1] containing the entries of val marked by 1-tags. Should be
something efficient, since the source lists may be large (10^6 to 10^7). Thanks.
- References:
- Mapping tag-value lists to a third
- From: carlos.felippa%colorado.edu@gtempaccount.com
- Mapping tag-value lists to a third