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% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/data_to_wide.R
\name{data_to_wide}
\alias{data_to_wide}
\alias{reshape_wider}
\title{Reshape (pivot) data from long to wide}
\usage{
data_to_wide(
data,
id_cols = NULL,
values_from = "Value",
names_from = "Name",
names_sep = "_",
names_prefix = "",
names_glue = NULL,
values_fill = NULL,
verbose = TRUE,
...
)
reshape_wider(
data,
id_cols = NULL,
values_from = "Value",
names_from = "Name",
names_sep = "_",
names_prefix = "",
names_glue = NULL,
values_fill = NULL,
verbose = TRUE,
...
)
}
\arguments{
\item{data}{A data frame to convert to wide format, so that it has more
columns and fewer rows post-widening than pre-widening.}
\item{id_cols}{The name of the column that identifies the rows in the data
by which observations are grouped and the gathered data is spread into new
columns. Usually, this is a variable containing an ID for observations that
have been repeatedly measured. If \code{NULL}, it will use all remaining columns
that are not in \code{names_from} or \code{values_from} as ID columns. \code{id_cols} can
also be a character vector with more than one name of identifier columns. See
also 'Details' and 'Examples'.}
\item{values_from}{The name of the columns in the original data that contains
the values used to fill the new columns created in the widened data.}
\item{names_from}{The name of the column in the original data whose values
will be used for naming the new columns created in the widened data. Each
unique value in this column will become the name of one of these new columns.
In case \code{names_prefix} is provided, column names will be concatenated with
the string given in \code{names_prefix}.}
\item{names_sep}{If \code{names_from} or \code{values_from} contains multiple variables,
this will be used to join their values together into a single string to use
as a column name.}
\item{names_prefix}{String added to the start of every variable name. This is
particularly useful if \code{names_from} is a numeric vector and you want to create
syntactic variable names.}
\item{names_glue}{Instead of \code{names_sep} and \code{names_prefix}, you can supply a
\href{https://glue.tidyverse.org/index.html}{glue specification} that uses the
\code{names_from} columns to create custom column names. Note that the only
delimiters supported by \code{names_glue} are curly brackets, \verb{\{} and \verb{\}}.}
\item{values_fill}{Optionally, a (scalar) value that will be used to replace
missing values in the new columns created.}
\item{verbose}{Toggle warnings.}
\item{...}{Not used for now.}
}
\value{
If a tibble was provided as input, \code{data_to_wide()} also returns a
tibble. Otherwise, it returns a data frame.
}
\description{
This function "widens" data, increasing the number of columns and decreasing
the number of rows. This is a dependency-free base-R equivalent of
\code{tidyr::pivot_wider()}.
}
\details{
Reshaping data into wide format usually means that the input data frame is
in \emph{long} format, where multiple measurements taken on the same subject are
stored in multiple rows. The wide format stores the same information in a
single row, with each measurement stored in a separate column. Thus, the
necessary information for \code{data_to_wide()} is:
\itemize{
\item The name of the column(s) that identify the groups or repeated measurements
(\code{id_cols}).
\item The name of the column whose \emph{values} will become the new column names
(\code{names_from}). Since these values may not necessarily reflect appropriate
column names, you can use \code{names_prefix} to add a prefix to each newly
created column name.
\item The name of the column that contains the values (\code{values_from}) for the
new columns that are created by \code{names_from}.
}
In other words: repeated measurements, as indicated by \code{id_cols}, that are
saved into the column \code{values_from} will be spread into new columns, which
will be named after the values in \code{names_from}. See also 'Examples'.
}
\examples{
\dontshow{if (requireNamespace("lme4", quietly = TRUE)) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
data_long <- read.table(header = TRUE, text = "
subject sex condition measurement
1 M control 7.9
1 M cond1 12.3
1 M cond2 10.7
2 F control 6.3
2 F cond1 10.6
2 F cond2 11.1
3 F control 9.5
3 F cond1 13.1
3 F cond2 13.8
4 M control 11.5
4 M cond1 13.4
4 M cond2 12.9")
# converting long data into wide format
data_to_wide(
data_long,
id_cols = "subject",
names_from = "condition",
values_from = "measurement"
)
# converting long data into wide format with custom column names
data_to_wide(
data_long,
id_cols = "subject",
names_from = "condition",
values_from = "measurement",
names_prefix = "Var.",
names_sep = "."
)
# converting long data into wide format, combining multiple columns
production <- expand.grid(
product = c("A", "B"),
country = c("AI", "EI"),
year = 2000:2014
)
production <- data_filter(production, (product == "A" & country == "AI") | product == "B")
production$production <- rnorm(nrow(production))
data_to_wide(
production,
names_from = c("product", "country"),
values_from = "production",
names_glue = "prod_{product}_{country}"
)
# using the "sleepstudy" dataset
data(sleepstudy, package = "lme4")
# the sleepstudy data contains repeated measurements of average reaction
# times for each subjects over multiple days, in a sleep deprivation study.
# It is in long-format, i.e. each row corresponds to a single measurement.
# The variable "Days" contains the timepoint of the measurement, and
# "Reaction" contains the measurement itself. Converting this data to wide
# format will create a new column for each day, with the reaction time as the
# value.
head(sleepstudy)
data_to_wide(
sleepstudy,
id_cols = "Subject",
names_from = "Days",
values_from = "Reaction"
)
# clearer column names
data_to_wide(
sleepstudy,
id_cols = "Subject",
names_from = "Days",
values_from = "Reaction",
names_prefix = "Reaction_Day_"
)
# For unequal group sizes, missing information is filled with NA
d <- subset(sleepstudy, Days \%in\% c(0, 1, 2, 3, 4))[c(1:9, 11:13, 16:17, 21), ]
# long format, different number of "Subjects"
d
data_to_wide(
d,
id_cols = "Subject",
names_from = "Days",
values_from = "Reaction",
names_prefix = "Reaction_Day_"
)
# filling missing values with 0
data_to_wide(
d,
id_cols = "Subject",
names_from = "Days",
values_from = "Reaction",
names_prefix = "Reaction_Day_",
values_fill = 0
)
\dontshow{\}) # examplesIf}
}
\seealso{
\itemize{
\item Add a prefix or suffix to column names: \code{\link[=data_addprefix]{data_addprefix()}}, \code{\link[=data_addsuffix]{data_addsuffix()}}
\item Functions to reorder or remove columns: \code{\link[=data_reorder]{data_reorder()}}, \code{\link[=data_relocate]{data_relocate()}},
\code{\link[=data_remove]{data_remove()}}
\item Functions to reshape, pivot or rotate data frames: \code{\link[=data_to_long]{data_to_long()}},
\code{\link[=data_to_wide]{data_to_wide()}}, \code{\link[=data_rotate]{data_rotate()}}
\item Functions to recode data: \code{\link[=rescale]{rescale()}}, \code{\link[=reverse]{reverse()}}, \code{\link[=categorize]{categorize()}},
\code{\link[=recode_values]{recode_values()}}, \code{\link[=slide]{slide()}}
\item Functions to standardize, normalize, rank-transform: \code{\link[=center]{center()}}, \code{\link[=standardize]{standardize()}},
\code{\link[=normalize]{normalize()}}, \code{\link[=ranktransform]{ranktransform()}}, \code{\link[=winsorize]{winsorize()}}
\item Split and merge data frames: \code{\link[=data_partition]{data_partition()}}, \code{\link[=data_merge]{data_merge()}}
\item Functions to find or select columns: \code{\link[=data_select]{data_select()}}, \code{\link[=extract_column_names]{extract_column_names()}}
\item Functions to filter rows: \code{\link[=data_match]{data_match()}}, \code{\link[=data_filter]{data_filter()}}
}
}
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