https://github.com/hadley/dplyr
Tip revision: 39ee11bfe78c4a301070b00d3b92127217786ba7 authored by Hadley Wickham on 23 January 2020, 16:18:08 UTC
Preserve drop attr
Preserve drop attr
Tip revision: 39ee11b
new_grouped_df.Rd
% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/grouped-df.r
\name{new_grouped_df}
\alias{new_grouped_df}
\alias{validate_grouped_df}
\title{Low-level construction and validation for the grouped_df class}
\usage{
new_grouped_df(x, groups, ..., class = character())
validate_grouped_df(x, check_bounds = FALSE)
}
\arguments{
\item{x}{A data frame}
\item{groups}{The grouped structure, \code{groups} should be a data frame.
Its last column should be called \code{.rows} and be
a list of 1 based integer vectors that all are between 1 and the number of rows of \code{.data}.}
\item{...}{additional attributes}
\item{class}{additional class, will be prepended to canonical classes of a grouped data frame.}
\item{check_bounds}{whether to check all indices for out of bounds problems in grouped_df objects}
}
\description{
\code{new_grouped_df()} is a constructor designed to be high-performance so only
check types, not values. This means it is the caller's responsibility
to create valid values, and hence this is for expert use only.
\code{validate_grouped_df()} validates the attributes of a \code{grouped_df}.
}
\examples{
# 5 bootstrap samples
tbl <- new_grouped_df(
tibble(x = rnorm(10)),
groups = tibble(".rows" := replicate(5, sample(1:10, replace = TRUE), simplify = FALSE))
)
# mean of each bootstrap sample
summarise(tbl, x = mean(x))
}
\keyword{internal}