rownames {tibble}

Tools for working with row names

Description

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.

Usage

has_rownames(.data)

remove_rownames(.data)

rownames_to_column(.data, var = "rowname")

rowid_to_column(.data, var = "rowid")

column_to_rownames(.data, var = "rowname")

Arguments

.data

A data frame.

var

Name of column to use for rownames.

Value

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.

Examples

# Detect row names ----------------------------------------------------
has_rownames(mtcars)
has_rownames(trees)

# Remove row names ----------------------------------------------------
remove_rownames(mtcars) %>% has_rownames()

# Convert between row names and column --------------------------------
mtcars_tbl <- rownames_to_column(mtcars, var = "car") %>% as_tibble()
mtcars_tbl
column_to_rownames(mtcars_tbl, var = "car") %>% head()

# Adding rowid as a column --------------------------------------------
rowid_to_column(trees) %>% head()