Odp: Need a more efficient way to implement this type of logic in R
Hi r-help-bounces at r-project.org napsal dne 06.04.2011 22:02:29:
I have cobbled together the following logic. It works but is very
slow. I'm sure that there must be a better r-specific way to implement
this kind of thing, but have been unable to find/understand one. Any
help would be appreciated.
hh.sub <- households[c("HOUSEID","HHFAMINC")]
for (indx in 1:length(hh.sub$HOUSEID)) {
if ((hh.sub$HHFAMINC[indx] == '01') | (hh.sub$HHFAMINC[indx] == '02')
| (hh.sub$HHFAMINC[indx] == '03') | (hh.sub$HHFAMINC[indx] == '04') |
(hh.sub$HHFAMINC[indx] == '05'))
hh.sub$CS_FAMINC[indx] <- 1 # Less than $25,000
if ((hh.sub$HHFAMINC[indx] == '06') | (hh.sub$HHFAMINC[indx] == '07')
| (hh.sub$HHFAMINC[indx] == '08') | (hh.sub$HHFAMINC[indx] == '09') |
(hh.sub$HHFAMINC[indx] == '10'))
hh.sub$CS_FAMINC[indx] <- 2 # $25,000 to $50,000
if ((hh.sub$HHFAMINC[indx] == '11') | (hh.sub$HHFAMINC[indx] == '12')
| (hh.sub$HHFAMINC[indx] == '13') | (hh.sub$HHFAMINC[indx] == '14') |
(hh.sub$HHFAMINC[indx] == '15'))
hh.sub$CS_FAMINC[indx] <- 3 # $50,000 to $75,000
if ((hh.sub$HHFAMINC[indx] == '16') | (hh.sub$HHFAMINC[indx] ==
'17'))
hh.sub$CS_FAMINC[indx] <- 4 # $75,000 to $100,000
if ((hh.sub$HHFAMINC[indx] == '18'))
hh.sub$CS_FAMINC[indx] <- 5 # More than $100,000
if ((hh.sub$HHFAMINC[indx] == '-7') | (hh.sub$HHFAMINC[indx] == '-8')
| (hh.sub$HHFAMINC[indx] == '-9'))
hh.sub$CS_FAMINC[indx] = 0
}
Take advantage of factors. If hh.sub$HHFAMINC was factor you can recode it by levels(hh.sub$HHFAMINC)<-appropriate vector of new levels with the same length as levels Something like
x<-factor(letters[1:5]) x
[1] a b c d e Levels: a b c d e
levels(x)<-c(1,1,2,2,1) x
[1] 1 1 2 2 1 Levels: 1 2
Regards Petr
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