Tibble constructor and validator

Creates or validates a subclass of a tibble. These function is mostly useful for package authors that implement subclasses of a tibble, like sf or tsibble.

new_tibble() creates a new object as a subclass of tbl_df, tbl and data.frame. This function is optimized for performance, checks are reduced to a minimum. See vctrs::new_data_frame() for details.

validate_tibble() checks a tibble for internal consistency. Correct behavior can be guaranteed only if this function runs without raising an error.

Usage

new_tibble(x, ..., nrow = NULL, class = NULL, subclass = NULL)

validate_tibble(x)

Arguments

x

A tibble-like object.

...

Name-value pairs of additional attributes.

nrow

The number of rows, inferred from x if omitted.

class

Subclasses to assign to the new object, default: none.

subclass

Deprecated, retained for compatibility. Please use the class argument.

Construction

For new_tibble(), x must be a list. The nrow argument may be omitted as of tibble 3.1.4. If present, every element of the list x should have vctrs::vec_size() equal to this value. (But this is not checked by the constructor). This takes the place of the "row.names" attribute in a data frame. x must have names (or be empty), but the names are not checked for correctness.

Validation

validate_tibble() checks for "minimal" names and that all columns are vectors, data frames or matrices. It also makes sure that all columns have the same length, and that vctrs::vec_size() is consistent with the data.

See also

tibble() and as_tibble() for ways to construct a tibble with recycling of scalars and automatic name repair, and vctrs::df_list() and vctrs::new_data_frame() for lower-level implementations.

Examples

# The nrow argument can be omitted:
new_tibble(list(a = 1:3, b = 4:6))
#> # A tibble: 3 × 2
#>       a     b
#>   <int> <int>
#> 1     1     4
#> 2     2     5
#> 3     3     6

# Existing row.names attributes are ignored:
try(validate_tibble(new_tibble(trees, nrow = 3)))
#> Error in validate_nrow(names(x), col_lengths(x), vec_size(x)) : 
#>   Tibble columns must have compatible sizes.
#> • Size 3: Requested with `nrow` argument.
#> • Size 31: Columns `Girth`, `Height`, and `Volume`.
#> ℹ Only values of size one are recycled.

# The length of all columns must be compatible with the nrow argument:
try(validate_tibble(new_tibble(list(a = 1:3, b = 4:6), nrow = 2)))
#> Error in validate_nrow(names(x), col_lengths(x), vec_size(x)) : 
#>   Tibble columns must have compatible sizes.
#> • Size 2: Requested with `nrow` argument.
#> • Size 3: Columns `a` and `b`.
#> ℹ Only values of size one are recycled.