In R how to combine multiple string columns in an R dataframe into one list column

Question

I'm trying to combine multiple string columns in a data frame into a single list with multiple elements.

Here is some sample data:

Df = 
Note1   Note2   Note3   OtherStuff
“do”    na  “re”    54
“fa”    “so”    “ti”    na
“mi”    “do”    na  10

What I want is:

DF = 
Note1   Note2   Note3   OtherStuff  Notes1_3
“do”    na  “re”    54      c(“do”, na, “re”)
“fa”    “so”    “ti”    na      c(“fa”, “so”, “ti”)
“mi”    “do”    na  10      c(“mi”, “do, na)

I tried the code below as suggested in another Stackoverflow Q&A:

DF %>%
  mutate(Notes1_3 = mapply(c, Note1, Note2, Note3)

This resulted in Notes1_3 equal to NULL for all the rows in the dataframe. This looks like something that should be easy to do and I'm just missing some detail.

Answer 1

If you want Notes1_3 to be a list column as in the title, you just need to make it into a list, not a vector:

df <- structure(list(Note1 = c("“do”", "“fa”", "“mi”"), 
    Note2 = c("na", "“so”", "“do”"), Note3 = c("“re”", 
    "“ti”", "na"), OtherStuff = c("54", "na", "10")), class = "data.frame", row.names = c(NA, 
-3L))

df
  Note1 Note2 Note3 OtherStuff
1  “do”    na  “re”         54
2  “fa”  “so”  “ti”         na
3  “mi”  “do”    na         10

df2 <- df %>%
    mutate(Notes1_3 = list(Note1, Note2, Note3))

df2
  Note1 Note2 Note3 OtherStuff         Notes1_3
1  “do”    na  “re”         54 “do”, “fa”, “mi”
2  “fa”  “so”  “ti”         na   na, “so”, “do”
3  “mi”  “do”    na         10   “re”, “ti”, na

If we look specifically at that column, we see it's actually a list of vectors as desired:

df2$Notes1_3
[[1]]
[1] "“do”" "“fa”" "“mi”"

[[2]]
[1] "na"   "“so”" "“do”"

[[3]]
[1] "“re”" "“ti”" "na"