在R中的子集数据框中替换多个列值

Question

I want to replace some values of a subset dataframe in R like:

The dataframe I work with:

sw1<- swiss[1:5, 1:4]
sw2 <- rbind(sw1,sw1)

Here is the subset as defined by some index criteria:

sw2[sw2$Examination==15 & sw2$Education==12,]

where I want to replace the value for Examination and Education to 1 and 2 respectively. But how can I assign values to these cells so that I get a sw2 dataframe with the correct values.

Answer 1

In your question:

sw2 <- rbind(sw2,sw2)

Where does sw2 come from? I'm just going to assume your rbind() should have been:

sw2 <- rbind(sw1, sw1)

Anyway, you can replace those two columns like this:

sw2[sw2$Examination==15 & sw2$Education==12, c('Examination', 'Education')]  <- list(1, 2)

I am isolating the columns that need to be updated with c('Examination', 'Education') . list(1, 2) will automatically repeat for as many rows as you assign it to (two in this case).

Syntax is a bit funky so I would probably do something longer but easier to read.

m <- with(sw2, Examination == 15 & Education == 12)
sw2[m, 'Examination'] <- 1
sw2[m, 'Education'] <- 2