While a tibble can have row names (e.g., when converting from a regular data
frame), they are removed when subsetting with the [ operator.
A warning will be raised when attempting to assign non-NULL row names
to a tibble.
Generally, it is best to avoid row names, because they are basically a
character column with different semantics than every other column.
These functions allow to you detect if a data frame has row names
(has_rownames()), remove them (remove_rownames()), or convert
them back-and-forth between an explicit column (rownames_to_column()
and column_to_rownames()).
Also included is rowid_to_column(), which adds a column at the start of the
dataframe of ascending sequential row ids starting at 1. Note that this will
remove any existing row names.
has_rownames(.data) remove_rownames(.data) rownames_to_column(.data, var = "rowname") rowid_to_column(.data, var = "rowid") column_to_rownames(.data, var = "rowname")
| .data | A data frame. |
|---|---|
| var | Name of column to use for rownames. |
column_to_rownames() always returns a data frame.
has_rownames() returns a scalar logical.
All other functions return an object of the same class as the input.
# Detect row names ---------------------------------------------------- has_rownames(mtcars)#> [1] TRUEhas_rownames(iris)#> [1] FALSE# Remove row names ---------------------------------------------------- remove_rownames(mtcars) %>% has_rownames()#> [1] FALSE# Convert between row names and column -------------------------------- mtcars_tbl <- rownames_to_column(mtcars, var = "car") %>% as_tibble() mtcars_tbl#> # A tibble: 32 x 12 #> car mpg cyl disp hp drat wt qsec vs am gear carb #> <chr> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> #> 1 Mazda RX4 21 6 160 110 3.9 2.62 16.5 0 1 4 4 #> 2 Mazda RX4 … 21 6 160 110 3.9 2.88 17.0 0 1 4 4 #> 3 Datsun 710 22.8 4 108 93 3.85 2.32 18.6 1 1 4 1 #> 4 Hornet 4 D… 21.4 6 258 110 3.08 3.22 19.4 1 0 3 1 #> 5 Hornet Spo… 18.7 8 360 175 3.15 3.44 17.0 0 0 3 2 #> 6 Valiant 18.1 6 225 105 2.76 3.46 20.2 1 0 3 1 #> 7 Duster 360 14.3 8 360 245 3.21 3.57 15.8 0 0 3 4 #> 8 Merc 240D 24.4 4 147. 62 3.69 3.19 20 1 0 4 2 #> 9 Merc 230 22.8 4 141. 95 3.92 3.15 22.9 1 0 4 2 #> 10 Merc 280 19.2 6 168. 123 3.92 3.44 18.3 1 0 4 4 #> # … with 22 more rows#> mpg cyl disp hp drat wt qsec vs am gear carb #> Mazda RX4 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4 #> Mazda RX4 Wag 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4 #> Datsun 710 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1 #> Hornet 4 Drive 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1 #> Hornet Sportabout 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2 #> Valiant 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1# Adding rowid as a column -------------------------------------------- rowid_to_column(iris) %>% head()#> rowid Sepal.Length Sepal.Width Petal.Length Petal.Width Species #> 1 1 5.1 3.5 1.4 0.2 setosa #> 2 2 4.9 3.0 1.4 0.2 setosa #> 3 3 4.7 3.2 1.3 0.2 setosa #> 4 4 4.6 3.1 1.5 0.2 setosa #> 5 5 5.0 3.6 1.4 0.2 setosa #> 6 6 5.4 3.9 1.7 0.4 setosa