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Assert that a data frame has an exact number of columns

Source: R/data_frame.R
assert_number_of_columns.Rd

Assert that a data frame has an exact number of columns

Usage

assert_number_of_columns(
  x,
  expected_columns,
  null_ok = FALSE,
  arg = rlang::caller_arg(x),
  call = rlang::caller_env()
)

Arguments

x

Object to check.

expected_columns

Single non-negative whole number: the required column count.

null_ok

Single logical. If TRUE, a NULL value passes the check without error. Use this for optional arguments that default to NULL. Defaults to FALSE, so NULL is rejected unless you opt in.

arg

Name used to refer to x in error messages. Defaults to the name of the expression passed as x.

call

Environment used as the error's call context. Defaults to the calling function, so errors point at the user's code.

Value

The input x, invisibly.

Examples

assert_number_of_columns(data.frame(a = 1, b = 2), 2)