Ifelse not working

General
1

I am using ifelse to filter from a vector of characters.

file_list=c("a.csv","b.csv","c.csv","d.csv","e.csv","f.csv")

rmd_list=c("c.csv","d.csv","e.csv","f.csv")


input=as.list(c("Tom","Brad"))
RCM=input[[1]]


ifelse(RCM %in% "Tom",file_list[!file_list%in%rmd_list],0)

The output suppose to show "a.csv" and "b.csv"

2

The ifelse() function returns a vector the same length as the test expression, which in this case is 1.

length(RCM %in% "Tom")
#> [1] 1

Instead, you can use if...else.

if(RCM %in% "Tom") {file_list[!file_list %in% rmd_list]} else {0}
#> [1] "a.csv" "b.csv"

Created on 2023-02-03 with reprex v2.0.2.9000

3

ifelse steps along the vectors in its arguments. Since RCM is of length 1, it only returns one value. This illustration might help you see what ifelse does.

ifelse(c("Tom","Brad","Alice","Tom") %in% "Tom", c(1,2,3,4),c(11,22,33,44))
[1]  1 22 33  4
4

Compare with

 "Tom" %in% RCM