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tidyr

Overview

The goal of tidyr is to help you create tidy data. Tidy data is data where:

  1. Each variable is in a column.
  2. Each observation is a row.
  3. Each value is a cell.

Tidy data describes a standard way of storing data that is used wherever possible throughout the tidyverse. If you ensure that your data is tidy, you’ll spend less time fighting with the tools and more time working on your analysis.

Installation

# The easiest way to get tidyr is to install the whole tidyverse:
install.packages("tidyverse")

# Alternatively, install just tidyr:
install.packages("tidyr")

# Or the development version from GitHub:
# install.packages("devtools")
devtools::install_github("tidyverse/tidyr")

Cheatsheet

Getting started

library(tidyr)

There are two fundamental verbs of data tidying:

  • gather() takes multiple columns, and gathers them into key-value pairs: it makes “wide” data longer.

  • spread() takes two columns (key & value), and spreads into multiple columns: it makes “long” data wider.

tidyr also provides separate() and extract() functions which makes it easier to pull apart a column that represents multiple variables. The complement to separate() is unite().

To get started, read the tidy data vignette (vignette("tidy-data")) and check out the demos (demo(package = "tidyr")).

Related work

tidyr replaces reshape2 (2010-2014) and reshape (2005-2010). Somewhat counterintuitively each iteration of the package has done less. tidyr is designed specifically for tidying data, not general reshaping (reshape2), or the general aggregation (reshape).

If you’d like to read more about data reshaping from a CS perspective, I’d recommend the following three papers:

To guide your reading, here’s a translation between the terminology used in different places:

tidyrgatherspread
reshape(2)meltcast
spreadsheetsunpivotpivot
databasesfoldunfold

Getting help

If you encounter a clear bug, please file a minimal reproducible example on github. For questions and other discussion, please use community.rstudio.com.


Please note that the tidyr project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.

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Version

Install

install.packages('tidyr')

Monthly Downloads

1,202,383

Version

0.8.3

License

MIT + file LICENSE

Issues

Pull Requests

Stars

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Maintainer

Last Published

March 1st, 2019

Functions in tidyr (0.8.3)

fill

Fill in missing values.
full_seq

Create the full sequence of values in a vector.
separate

Separate one column into multiple columns.
separate_rows

Separate a collapsed column into multiple rows.
gather

Gather columns into key-value pairs.
spread

Spread a key-value pair across multiple columns.
extract

Extract one column into multiple columns.
complete

Complete a data frame with missing combinations of data.
extract_numeric

Extract numeric component of variable.
nest

Nest repeated values in a list-variable.
uncount

"Uncount" a data frame
table1

Example tabular representations
unite

Unite multiple columns into one.
unnest

Unnest a list column.
who

World Health Organization TB data
tidyr-package

tidyr: Easily Tidy Data with 'spread()' and 'gather()' Functions
deprecated-se

Deprecated SE versions of main verbs
%>%

Pipe operator
replace_na

Replace missing values
drop_na

Drop rows containing missing values
expand

Expand data frame to include all combinations of values
smiths

Some data about the Smith family.