revalue data with multiple conditions in r

Question

I extracted a vector from a dataframe. The df looks like this:

from  type
 23    U
 25    U
 30    S
 32    S
 50    T
 60    T

and the vector:

vec<-c("23","30","50")

Now I want to search for the values defined by the vector in the df. If the value in the df is part of the vector then I want to paste the type variable in front of the from variable.

I tried to look up the vector with dplyr::filter.

df<-df %>% filter(from %in% vec && type=="U") %>% mutate(from=paste(type,from,sep=""))

Now I don't know how to proceed as my approach doesn't work out. Not sure whether a if-else statement would be more appropriate.

expected results are:

from  type
 U23   U
 25    U
 S30   S
 32    S
 T50   T
 60    T

Thank you in advance!

Answer 1

You could do:

df %>% 
  mutate(from = ifelse(from %in% vec, paste0(type, from), from))

  from type
1  U23    U
2   25    U
3  S30    S
4   32    S
5  T50    T
6   60    T

Data:

df <- read.table(text = "
 from  type
 23    U
 25    U
 30    S
 32    S
 50    T
 60    T", h =T)


vec<-c("23","30","50")