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% File src/library/base/man/pipeOp.Rd
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% File src/library/base/man/pipeOp.Rd
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% Part of the R package, https://www.R-project.org
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% Part of the R package, https://www.R-project.org
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% Copyright 1995-2022 R Core Team
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% Copyright 1995-2024 R Core Team
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% Distributed under GPL 2 or later
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% Distributed under GPL 2 or later
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\name{pipeOp}
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\name{pipeOp}
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\alias{|>}
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\alias{|>}
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\alias{pipeOp}
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\alias{pipeOp}
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\arguments{
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\arguments{
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\item{lhs}{expression producing a value.}
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\item{lhs}{expression producing a value.}
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\item{rhs}{a call expression.}% or an expression of the form \code{symbol => call}
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\item{rhs}{a call expression.}% or an expression of the form \code{symbol => call}
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}
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}
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\details{
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\details{
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A pipe expression passes, or pipes, the result of the left-hand side
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A pipe expression passes, or \sQuote{pipes}, the result of the left-hand-side
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expression \code{lhs} to the right-hand side expression \code{rhs}.
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expression \code{lhs} to the right-hand-side expression \code{rhs}.
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The \code{lhs} is
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The \code{lhs} is
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inserted as the first argument in the call. So \code{x |> f(y)} is
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inserted as the first argument in the call. So \code{x |> f(y)} is
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interpreted as \code{f(x, y)}.
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interpreted as \code{f(x, y)}.
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Pipe notation allows a nested sequence of calls to be written in a way
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Pipe notation allows a nested sequence of calls to be written in a way
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that may make the sequence of processing steps easier to follow.
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that may make the sequence of processing steps easier to follow.
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Currently, pipe operations are implemented as syntax transformations.
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Currently, pipe operations are implemented as syntax transformations.
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So an expression written as \code{x |> f(y)} is parsed as \code{f(x,
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So an expression written as \code{x |> f(y)} is parsed as \code{f(x,
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y)}. It is worth emphasizing that while the code in a pipeline is
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y)}. It is worth emphasizing that while the code in a pipeline is
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written sequentially, regular R semantics for evaluation apply and
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written sequentially, regular R semantics for evaluation apply and
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so piped expressions will be evaluated only when first used in the
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so piped expressions will be evaluated only when first used in the
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\code{rhs} expression.
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\code{rhs} expression.
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}
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}
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\value{
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\value{
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Returns the result of evaluating the transformed expression.
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Returns the result of evaluating the transformed expression.
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}
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}
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\section{Background}{
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\section{Background}{
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The forward pipe operator is motivated by the pipe introduced in the
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The forward pipe operator is motivated by the pipe introduced in the
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\CRANpkg{magrittr} package, but is more streamlined. It is similar to
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\CRANpkg{magrittr} package, but is more streamlined. It is similar to
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the pipe or pipeline operators introduced in other languages, including
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the pipe or pipeline operators introduced in other languages, including
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F#, Julia, and JavaScript.
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F#, Julia, and JavaScript.
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}
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}
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\section{Warning}{
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This was introduced in \R 4.1.0. Code using it will not be parsed
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as intended (probably with an error) in earlier versions of \R.
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}
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\examples{
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\examples{
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# simple uses:
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# simple uses:
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mtcars |> head() # same as head(mtcars)
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mtcars |> head() # same as head(mtcars)
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mtcars |> head(2) # same as head(mtcars, 2)
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mtcars |> head(2) # same as head(mtcars, 2)
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mtcars |> subset(cyl == 4) |> nrow() # same as nrow(subset(mtcars, cyl == 4))
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mtcars |> subset(cyl == 4) |> nrow() # same as nrow(subset(mtcars, cyl == 4))
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