In some quarters, it is considered best to avoid row names, because they are effectively 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.

rownames_to_column(.data, var = "rowname")

rowid_to_column(.data, var = "rowid")

column_to_rownames(.data, var = "rowname")

remove_rownames(.data)

has_rownames(.data)

Arguments

.data

A data.frame.

var

character(1). The name of the column to use for row names.

Value

  • column_to_rownames() always returns a data.frame.

  • has_rownames() returns a logical(1).

  • All other functions return an object of the same class as the input.

Examples

# Detect row names has_rownames(mtcars)
#> [1] TRUE
has_rownames(iris)
#> [1] FALSE
# Remove row names remove_rownames(mtcars) %>% has_rownames()
#> [1] FALSE
# Convert between row names and column mtcars <- rownames_to_column(mtcars, var = "car") column_to_rownames(mtcars, var = "car") %>% head()
#> 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