Creates a data frame with specified column types and validation rules. Ensures that the data frame adheres to the specified structure and validation rules during creation and modification.
Usage
type.frame(
frame,
col_types,
freeze_n_cols = TRUE,
row_callback = NULL,
allow_na = TRUE,
on_violation = c("error", "warning", "silent")
)Arguments
- frame
The base data structure (e.g., data.frame, data.table).
- col_types
A list of column types and validators.
- freeze_n_cols
Logical, whether to freeze the number of columns (default: TRUE).
- row_callback
A function to validate and process each row (optional).
- allow_na
Logical, whether to allow NA values (default: TRUE).
- on_violation
Action to take on violation: "error", "warning", or "silent" (default: "error").
Value
A function that creates typed data frames. When called, this function returns an object of class 'typed_frame' (which also inherits from the base frame class used, i.e. data.frame, data.table).
Details
The `type.frame` function defines a blueprint for a data frame, specifying the types of its columns and optional validation rules for its rows. When a data frame is created or modified using this blueprint, it ensures that all data adheres to the specified rules.
Examples
# Define a typed data frame
PersonFrame <- type.frame(
frame = data.frame,
col_types = list(
id = integer,
name = character,
age = numeric,
is_student = logical
)
)
# Create a data frame
persons <- PersonFrame(
id = 1:3,
name = c("Alice", "Bob", "Charlie"),
age = c(25, 30, 35),
is_student = c(TRUE, FALSE, TRUE)
)
print(persons)
#> Typed Data Frame Summary:
#> Base Frame Type: data.frame
#> Dimensions: 3 rows x 4 columns
#>
#> Column Specifications:
#> id : integer
#> name : character
#> age : numeric
#> is_student : logical
#>
#> Frame Properties:
#> Freeze columns : Yes
#> Allow NA : Yes
#> On violation : error
#>
#> Data Preview:
#> id name age is_student
#> 1 1 Alice 25 TRUE
#> 2 2 Bob 30 FALSE
#> 3 3 Charlie 35 TRUE
# Invalid modification (throws error)
try(persons$id <- letters[1:3])
#> Error : Property 'id' must be of type integer
# Adding a column (throws error if freeze_n_cols is TRUE)
try(persons$yeet <- letters[1:3])
#> Error in `$<-.typed_frame`(`*tmp*`, yeet, value = c("a", "b", "c")) :
#> Adding new columns is not allowed when freeze_n_cols is TRUE