skim-obj: Test if an object is compatible with `skimr`

Description

Objects within skimr are identified by a class, but they require additional attributes and data columns for all operations to succeed. These checks help ensure this. While they have some application externally, they are mostly used internally.

Usage

has_type_column(object)
has_variable_column(object)
has_skimr_attributes(object)
is_skim_df(object)
assert_is_skim_df(object)
is_skim_list(object)
assert_is_skim_list(object)
could_be_skim_df(object)

Arguments

object

Any R object.

Functions

has_type_column: Does the object have the skim_type column?
has_variable_column: Does the object have the skim_variable column?
has_skimr_attributes: Does the object have the appropriate skimr attributes?
is_skim_df: Is the object a skim_df?
assert_is_skim_df: Stop if the object is not a skim_df.
is_skim_list: Is the object a skim_list?
assert_is_skim_list: Stop if the object is not a skim_list.
could_be_skim_df: Is this a data frame with skim_variable and skim_type columns?

Details

Most notably, a skim_df

has columns skim_type and skim_variable
has more than zero rows

And has the following special attributes

data_rows: n rows in the original data
data_cols: original number of columns
df_name: name of the original data frame
groups: if there were group variables
base_skimmers: names of functions applied to all skim types
skimmers_used: names of functions used to skim each type