Re: Speeding up a for loop

["David L Lorenz" <lorenz@usgs.gov>]

Gerald,
  Why not merge the data frames on newprof and CodeProf and then make the
assignment?
Dave



                                                                                
                                                  
                      gerald.jean@dgag.ca                                       
                                                  
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                      t.wustl.edu                      Subject:  [S] Speeding 
up a for loop                                       
                                                                                
                                                  
                                                                                
                                                  
                      11/24/2004 08:07 AM                                       
                                                  
                                                                                
                                                  
                                                                                
                                                  




Hello S-users,

I am running the following loop at the top level --- not in a function ---
and it takes for ever!  It is running since 16h00 yesterday, hence over 17
hours so far.  It is not using too much memory though.  The data.frame it
is looping over is small, 284 observations, while the data.frame where the
assignements take place is huge, over 2M records.  Since I have two more
data.frames, even bigger, where I have to run the same loop I am wondering
if there is a way to speed up this loop or another way to get the task
done?

> for (i in 1:nrow(StatCanCNP)) {
+   QcProf.Ass.b2[QcProf.Ass.b2[, 'newprof'] == StatCanCNP[i, 'CodeProf'],
+                 c('Educ', 'Indus')] <- StatCanCNP[i, c('Education',
'CdIndus')]
+ }

The variables "Educ" and "Indus" in the large data.frame have been created
beforehand.

Here are the specs of my installation.

S-PLUS : Copyright (c) 1988, 2004 Insightful Corp.
S : Copyright Lucent Technologies, Inc.
Version 6.2.1  for Sun SPARC, SunOS 5.8, 64-bit : 2004

Thanks for any clues,

Gérald Jean
Analyste-conseil (statistiques), Actuariat
télephone            : (418) 835-4900 poste (7639)
télecopieur          : (418) 835-6657
courrier électronique: gerald.jean@dgag.ca

"In God we trust all others must bring data"  W. Edwards Deming


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