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This function is comparable to dplyr::group_by(), but just following the datawizard function design. data_ungroup() removes the grouping information from a grouped data frame.


  select = NULL,
  exclude = NULL,
  ignore_case = FALSE,
  verbose = TRUE,

data_ungroup(x, verbose = TRUE, ...)



A data frame


Variables that will be included when performing the required tasks. Can be either

  • a variable specified as a literal variable name (e.g., column_name),

  • a string with the variable name (e.g., "column_name"), or a character vector of variable names (e.g., c("col1", "col2", "col3")),

  • a formula with variable names (e.g., ~column_1 + column_2),

  • a vector of positive integers, giving the positions counting from the left (e.g. 1 or c(1, 3, 5)),

  • a vector of negative integers, giving the positions counting from the right (e.g., -1 or -1:-3),

  • one of the following select-helpers: starts_with(""), ends_with(""), contains(""), a range using : or regex(""),

  • or a function testing for logical conditions, e.g. is.numeric() (or is.numeric), or any user-defined function that selects the variables for which the function returns TRUE (like: foo <- function(x) mean(x) > 3),

  • ranges specified via literal variable names, select-helpers (except regex()) and (user-defined) functions can be negated, i.e. return non-matching elements, when prefixed with a -, e.g. -ends_with(""), -is.numeric or -Sepal.Width:Petal.Length. Note: Negation means that matches are excluded, and thus, the exclude argument can be used alternatively. For instance, select=-ends_with("Length") (with -) is equivalent to exclude=ends_with("Length") (no -). In case negation should not work as expected, use the exclude argument instead.

If NULL, selects all columns. Patterns that found no matches are silently ignored, e.g. find_columns(iris, select = c("Species", "Test")) will just return "Species".


See select, however, column names matched by the pattern from exclude will be excluded instead of selected. If NULL (the default), excludes no columns.


Logical, if TRUE and when one of the select-helpers or a regular expression is used in select, ignores lower/upper case in the search pattern when matching against variable names.


Toggle warnings.


Arguments passed down to other functions. Mostly not used yet.


A grouped data frame, i.e. a data frame with additional information about the grouping structure saved as attributes.


if (requireNamespace("poorman")) {
  suppressPackageStartupMessages(library(poorman, quietly = TRUE))

  # total mean
  efc %>%
    summarize(mean_hours = mean(c12hour, na.rm = TRUE))

  # mean by educational level
  efc %>%
    data_group(c172code) %>%
    summarize(mean_hours = mean(c12hour, na.rm = TRUE))
#> Loading required namespace: poorman
#> # A tibble: 3 × 2
#> # Groups:   c172code [3]
#>   c172code mean_hours
#>      <dbl>      <dbl>
#> 1        1       87.1
#> 2        2       94.0
#> 3        3       75