pipeOp {base} | R Documentation |

Pipe a value into a call expression or a function expression.

```
lhs |> rhs
```

`lhs` |
expression producing a value. |

`rhs` |
a call expression. |

A pipe expression passes, or pipes, the result of the left-hand side
expression `lhs`

to the right-hand side expression `rhs`

.

The `lhs`

is
inserted as the first argument in the call. So `x |> f(y)`

is
interpreted as `f(x, y)`

.

To avoid ambiguities, functions in `rhs`

calls may not be
syntactically special, such as `+`

or `if`

.

It is also possible to use a named argument with the placeholder
`_`

in the `rhs`

call to specify where the `lhs`

is to
be inserted. The placeholder can only appear once on the `rhs`

.

Pipe notation allows a nested sequence of calls to be written in a way that may make the sequence of processing steps easier to follow.

Currently, pipe operations are implemented as syntax transformations.
So an expression written as `x |> f(y)`

is parsed as ```
f(x,
y)
```

. It is worth emphasizing that while the code in a pipeline is
written sequentially, regular R semantics for evaluation apply and
so piped expressions will be evaluated only when first used in the
`rhs`

expression.

Returns the result of evaluating the transformed expression.

The forward pipe operator is motivated by the pipe introduced in the magrittr package, but is more streamlined. It is similar to the pipe or pipeline operators introduced in other languages, including F#, Julia, and JavaScript.

```
# simple uses:
mtcars |> head() # same as head(mtcars)
mtcars |> head(2) # same as head(mtcars, 2)
mtcars |> subset(cyl == 4) |> nrow() # same as nrow(subset(mtcars, cyl == 4))
# to pass the lhs into an argument other than the first, either
# use the _ placeholder with a named argument:
mtcars |> subset(cyl == 4) |> lm(mpg ~ disp, data = _)
# or use an anonymous function:
mtcars |> subset(cyl == 4) |> (function(d) lm(mpg ~ disp, data = d))()
mtcars |> subset(cyl == 4) |> (\(d) lm(mpg ~ disp, data = d))()
# or explicitly name the argument(s) before the "one":
mtcars |> subset(cyl == 4) |> lm(formula = mpg ~ disp)
# the pipe operator is implemented as a syntax transformation:
quote(mtcars |> subset(cyl == 4) |> nrow())
# regular R evaluation semantics apply
stop() |> (function(...) {})() # stop() is not used on RHS so is not evaluated
```

[Package *base* version 4.3.0 Index]