Need a more efficient way to implement this type of logic in R
On 06/04/2011 4:02 PM, Walter Anderson wrote:
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 $25,000
The answer is to think in terms of vectors and logical indexing. The
code above is equivalent to
hh.sub$CS_FAMINC[ hh.sub$HHFAMINC %in% c('01', '02', '03', '04', '05') ]
<- 1
I've left off the rest of the loop, but I think it's similar.
Duncan Murdoch