I am having troubles adding column conditionally to a df. For instance, I would like to add class values to column VarB and VarC according to the value of Var A.
For instance, I would like to add 'yes' to VarB when VarA equals "a", "c" and "e" and "no" when it equals "b" and "d". Also, I would like to add "1" to VarC when VarA equals "a" or "e"; "2" to VarC when VarA equals "b" or "d"; and, "3" to VarC when VarA equals "c".
VarA
a
b
c
d
e
Any tips?
Maybe this could be useful
DF <- data.frame(VarA=letters[1:4]) # this is your data.frame
VarA
1 a
2 b
3 c
4 d
DF$VarB <- ifelse(VarA %in% c('a','c','e'), 'yes', 'no')
DF$VarC <- ifelse(VarA %in% c('a','e'), 1, ifelse(VarA %in% c('b','d'),2,3))
DF
VarA VarB VarC
1 a yes 1
2 b no 2
3 c yes 3
4 d no 2
You can use transform function as well.
DF <- data.frame(VarA=letters[1:4])
transform(DF,
VarB=ifelse(VarA %in% c('a','c','e'), 'yes', 'no'),
VarC=ifelse(VarA %in% c('a','e'), 1, ifelse(VarA %in% c('b','d'),2,3)))
VarA VarB VarC
1 a yes 1
2 b no 2
3 c yes 3
4 d no 2
transform() ;)Do something in the spirit of the following:
cond1 <- data$VarA %in% c("a","c","e")
data$VarB[cond1] <- "yes"
cond2 <- data$VarA %in% c("b","d")
data$VarB[cond2] <- "no"
cond3 <- data$VarA %in% c("a","e")
data$VarC[cond3] <- 1
cond4 <- data$VarA %in% c("b","d")
data$VarC[cond4] <- 2
And I'll leave you to do the the last one yourself.
cond2 and cond4 if you just do !cond1 and !cond3, respectively. e.g. data$VarB[!cond1] <- "no"