Learn R Programming

⚠️There's a newer version (1.8.9) of this package.Take me there.

plyr

plyr is a set of tools for a common set of problems: you need to split up a big data structure into homogeneous pieces, apply a function to each piece and then combine all the results back together. For example, you might want to:

fit the same model each patient subsets of a data frame
quickly calculate summary statistics for each group
perform group-wise transformations like scaling or standardising

It's already possible to do this with base R functions (like split and the apply family of functions), but plyr makes it all a bit easier with:

totally consistent names, arguments and outputs
convenient parallelisation through the foreach package
input from and output to data.frames, matrices and lists
progress bars to keep track of long running operations
built-in error recovery, and informative error messages
labels that are maintained across all transformations

Considerable effort has been put into making plyr fast and memory efficient, and in many cases plyr is as fast as, or faster than, the built-in equivalents.

A detailed introduction to plyr has been published in JSS: "The Split-Apply-Combine Strategy for Data Analysis", http://www.jstatsoft.org/v40/i01/. You can find out more at https://had.co.nz/plyr/, or track development at https://github.com/hadley/plyr. You can ask questions about plyr (and data manipulation in general) on the plyr mailing list. Sign up at https://groups.google.com/group/manipulatr.

Status

plyr is retired: this means only changes necessary to keep it on CRAN will be made. We recommend using dplyr (for data frames) or purrr (for lists) instead.

Copy Link

Version

Install

install.packages('plyr')

Monthly Downloads

381,014

Version

1.8.8

License

MIT + file LICENSE

Issues

Pull Requests

Stars

Forks

Repository

https://github.com/hadley/plyr

Homepage

http://had.co.nz/plyr

Maintainer

Last Published

November 11th, 2022

Functions in plyr (1.8.8)

as.data.frame.function

Make a function return a data frame.

Convert input to quoted variables.

Dimension names.

Split array, apply function, and return results in an array.

Convert split list to regular list.

Split array, apply function, and discard results.

Split array, apply function, and return results in a list.

Order a data frame by its colums.

Split array, apply function, and return results in a data frame.

Split data frame, apply function, and return results in a data frame.

create_progress_bar

Create progress bar.

Count the number of occurences.

Column-wise function.

Yearly batting records for all major league baseball players

Descending order.

Split data frame, apply function, and discard results.

Split data frame, apply function, and return results in an array.

Fail with specified value.

Evaluate a quoted list of variables.

Check if a data frame is empty.

Aggregate multiple functions into a single function.

Recursively join a list of data frames.

Number of dimensions.

Numeric id for a vector.

Compute a unique numeric id for each unique row in a data frame.

An indexed data frame.

Split list, apply function, and discard results.

Determine if a vector is discrete.

Capture current evaluation context.

Split list, apply function, and return results in a list.

An indexed array.

list_to_dataframe

List to data frame.

Construct an immutable data frame.

Is a formula? Checks if argument is a formula

Split iterator that returns values, not indices.

Split list, apply function, and return results in an array.

Call function with arguments in array or data frame, discarding results.

Split list, apply function, and return results in a data frame.

Split data frame, apply function, and return results in a list.

Join keys. Given two data frames, create a unique key for each row.

Call function with arguments in array or data frame, returning an array.

Join two data frames together.

plyr-deprecated

Deprecated Functions in Package plyr

Monthly ozone measurements over Central America.

Experimental iterator based version of llply.

Text progress bar with time.

plyr: the split-apply-combine paradigm for R.

Graphical progress bar, powered by Tk.

Graphical progress bar, powered by Windows.

Mutate a data frame by adding new or replacing existing columns.

Toggle row names between explicit and implicit.

Combine data.frames by row, filling in missing columns.

Call function with arguments in array or data frame, returning a list.

Text progress bar.

Call function with arguments in array or data frame, returning a data frame.

Null progress bar

Number of unique values.

Compute names of quoted variables.

Reduce dimensions.

Replicate expression and return results in a data frame.

Print quoted variables.

Function that always returns true.

rbind.fill.matrix

Bind matrices by row, and fill missing columns with NA.

Try, with default in case of error.

Generate labels for split data frame.

Round to multiple of any number.

Replicate expression and return results in a list.

Replicate expression and return results in a array.

Replicate expression and discard results.

Split an array by .margins.

Take a subset along an arbitrary dimension

Summarise a data frame.

Split a data frame by variables.

`Splat' arguments to a function.

Remove splitting variables from a data frame.

Apply with built in try. Uses compact, lapply and tryNULL

Replace specified values with new values, in a vector or factor.

Extract matching rows of a data frame.

List to vector.

Quick data frame.

Replace specified values with new values, in a factor or character vector.

Modify names by name, not position.

Quote variables to create a list of unevaluated expressions for later evaluation.

Vector aggregate.