util_expect_data_frame: Verify, that argument is a data frame
In dataquieR: Data Quality in Epidemiological Research

util_expect_data_frame

R Documentation

Verify, that argument is a data frame

Description

stops with an error, if not. will add the columns, and return the resulting extended data frame, and also updating the original data frame in the calling environment, if #' x is empty (data frames easily break to 0-columns in R, if they have not rows, e.g. using some split/rbind pattern)

Usage

util_expect_data_frame(
  x,
  col_names,
  convert_if_possible,
  custom_errors,
  dont_assign,
  keep_types = FALSE
)

Arguments

`x`	an object that is verified to be a `data.frame`.
`col_names`	column names x must contain or named list of predicates to check the columns (e.g., list(AGE=is.numeric, SEX=is.character))
`convert_if_possible`	if given, for each column, a lambda can be given similar to `col_names` check functions. This lambda would be used to try a conversion. If a conversion fails (returns `NA`, where the input was not ‘util_empty’), an error is still thrown, the data is converted, otherwise
`custom_errors`	list with error messages, specifically per column. names of the list are column names, values are messages (character).
`dont_assign`	set `TRUE` to keep `x` in the caller environment untouched
`keep_types`	logical keep types as possibly defined in a file, if the data frame is loaded from one. set `TRUE` for study data.