# Just when I thought I had the basic stuff mastered....
# This has been quite perplexing, thanks for any help
## Here's the example:
db1=data.frame(
olditems=c('soup','','','','nuts'),
prices=c(4.45, 3.25, 4.42, 2.25, 3.98))
db2=data.frame(
newitems=c('stew','crackers','tofu','goatsmilk','peanuts'))
str(db1) #factors and prices
str(db2) #new names, but I want *only* the updates
is.na(db1$olditems) #a little surprising that '' is not equal to NA
db1$olditems=='' #oh good, at least I can get to the blanks this way
db1$olditems[db1$olditems==''] #wait, only one item is returned?
db1[db1$olditems=='',] #somehow this works!
#how would I get the new item names into the old items column of db1??
# I was expecting that this would work:
# db1$olditems[db1$olditems=='']=
# db2$newitems[db1$olditems=='']
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