stabilize_df: Ensure a data frame argument meets expectations

In stbl: Stabilize Function Arguments

Ensure a data frame argument meets expectations

Description

stabilize_df() validates the structure and contents of a data frame. It can check that specific named columns are present and valid, that extra columns conform to a shared rule, that required column names are present, and that the row count is within specified bounds. stabilise_df(), stabilize_data_frame(), and stabilise_data_frame() are synonyms of stabilize_df().

Usage

stabilize_df(
  .x,
  ...,
  .extra_cols = NULL,
  .col_names = NULL,
  .min_rows = NULL,
  .max_rows = NULL,
  .allow_null = TRUE,
  .x_arg = caller_arg(.x),
  .call = caller_env(),
  .x_class = object_type(.x)
)

stabilise_df(
  .x,
  ...,
  .extra_cols = NULL,
  .col_names = NULL,
  .min_rows = NULL,
  .max_rows = NULL,
  .allow_null = TRUE,
  .x_arg = caller_arg(.x),
  .call = caller_env(),
  .x_class = object_type(.x)
)

stabilize_data_frame(
  .x,
  ...,
  .extra_cols = NULL,
  .col_names = NULL,
  .min_rows = NULL,
  .max_rows = NULL,
  .allow_null = TRUE,
  .x_arg = caller_arg(.x),
  .call = caller_env(),
  .x_class = object_type(.x)
)

stabilise_data_frame(
  .x,
  ...,
  .extra_cols = NULL,
  .col_names = NULL,
  .min_rows = NULL,
  .max_rows = NULL,
  .allow_null = TRUE,
  .x_arg = caller_arg(.x),
  .call = caller_env(),
  .x_class = object_type(.x)
)

Arguments

.x	The argument to stabilize.
...	Named stabilizer functions, such as ⁠stabilize_*⁠ functions (stabilize_chr(), etc) or functions produced by ⁠specify_*()⁠ functions (specify_chr(), etc). Each name corresponds to a required column in .x, and the function is used to validate that column.
.extra_cols	A single stabilizer function, such as a ⁠stabilize_*⁠ function (stabilize_chr(), etc) or a function produced by a ⁠specify_*()⁠ function (specify_chr(), etc). This function is used to validate all columns of .x that are not explicitly listed in .... If NULL (default), any extra columns will cause an error.
.col_names	(character) A character vector of column names that must be present in .x. Any columns listed here that are absent from .x will cause an error. Unlike ..., this does not validate the column contents.
.min_rows	⁠(length-1 integer)⁠ The minimum number of rows allowed in .x. If NULL (default), the row count is not checked.
.max_rows	⁠(length-1 integer)⁠ The maximum number of rows allowed in .x. If NULL (default), the row count is not checked.
.allow_null	⁠(length-1 logical)⁠ Is NULL an acceptable value?
.x_arg	⁠(length-1 character)⁠ The name of the argument being stabilized to use in error messages. The automatic value will work in most cases, or pass it through from higher-level functions to make error messages clearer in unexported functions.
.call	(environment) The execution environment to mention as the source of error messages.
.x_class	⁠(length-1 character)⁠ The class name of the argument being stabilized to use in error messages. Use this if you remove a special class from the object before checking its coercion, but want the error message to match the original class.

Value

The validated data frame.

See Also

Other data frame functions: specify_df(), to_df()

Other stabilization functions: stabilize_arg(), stabilize_chr(), stabilize_dbl(), stabilize_fct(), stabilize_int(), stabilize_lgl(), stabilize_lst(), stabilize_present()

Examples

# Basic validation: required columns with type specs
stabilize_df(
  data.frame(name = "Alice", age = 30L),
  name = specify_chr_scalar(),
  age = specify_int_scalar()
)

# Allow extra columns with .extra_cols
stabilize_df(
  data.frame(name = "Alice", age = 30L, score = 99.5),
  name = specify_chr_scalar(),
  age = specify_int_scalar(),
  .extra_cols = stabilize_present
)

# Check required column names without validating contents
stabilize_df(
  mtcars,
  .col_names = c("mpg", "cyl"),
  .extra_cols = stabilize_present
)

# Enforce row count constraints
try(stabilize_df(mtcars[0, ], .min_rows = 1, .extra_cols = stabilize_present))

# NULL is allowed by default
stabilize_df(NULL)
try(stabilize_df(NULL, .allow_null = FALSE))

# Coercible inputs such as named lists are accepted
stabilize_df(
  list(name = "Alice", age = 30L),
  name = specify_chr_scalar(),
  age = specify_int_scalar()
)

# Non-coercible inputs are rejected
try(stabilize_df("not a data frame"))

stbl documentation built on April 4, 2026, 5:06 p.m.