I have this df:
df <- structure(list(a = 1:5, b = 6:10, c = 11:15, d = c("a", "b",
"c", "d", "e"), e = 1:5), row.names = c(NA, -5L), class = c("tbl_df",
"tbl", "data.frame"))
a b c d e
<int> <int> <int> <chr> <int>
1 1 6 11 a 1
2 2 7 12 b 2
3 3 8 13 c 3
4 4 9 14 d 4
5 5 10 15 e 5
rownames_to_column works:
df %>%
column_to_rownames(var="d") %>%
rownames_to_column(var= "d")
# Output
d a b c e
1 a 1 6 11 1
2 b 2 7 12 2
3 c 3 8 13 3
4 d 4 9 14 4
5 e 5 10 15 5
rownames_to_column works not properly (gives back the index?)
df %>%
column_to_rownames(var="d") %>%
rowwise() %>%
rownames_to_column(var= "d")
# Output:
d a b c e
<chr> <int> <int> <int> <int>
1 1 1 6 11 1
2 2 2 7 12 2
3 3 3 8 13 3
4 4 4 9 14 4
5 5 5 10 15 5
Why does this behaviour occur?
df originally is a tibble.
class(df)
[1] "tbl_df" "tbl" "data.frame"
When you use column_to_rownames it becomes a dataframe since tibbles can't have rownames.
df1 <- df %>% column_to_rownames(var="d")
class(df1)
#[1] "data.frame"
Next, when you use rowwise the data becomes converted to tibble again and rownames are now lost.
df2 <- df1 %>% rowwise()
class(df2)
#[1] "rowwise_df" "tbl_df" "tbl" "data.frame"
So when you do df2 %>% rownames_to_column(var = 'd') there are no rownames present hence you get a column d with row number.
rownames(df2)
#[1] "1" "2" "3" "4" "5"