Pondering the limitations of the built in R Pipe

The built-in base R pipe operator |> does not natively support the . pronoun used in the magrittr (%>%) pipe.

1. The Standard Alternative

To extract the first element using the base R pipe, you must wrap the subsetting operation inside an anonymous function.

# magrittr pipe
vector %>% .[1]

# Base R pipe alternative (R 4.1.0+)
vector |> {\(x) x[1]}()

2. The Shortcut Alternative

If you are using R 4.2.0 or newer, you can use the shortcut placeholder _ instead of an anonymous function. However, the placeholder must be passed into a named argument of a function, meaning you must use the standard extraction function `[`. [1]

# Base R pipe placeholder alternative (R 4.2.0+)
vector |> `[`(_, 1)

3. Dedicated Function Alternative

To avoid complex syntax, pass the piped object directly into a semantic indexing function like head().

# Cleanest functional alternative
vector |> head(1)

Summary of Rules for |>

• No implicit first argument: |> always pipes into the first argument unless the _ placeholder is used.
• Placeholder limits: The _ placeholder can only be used once in a function call.
• Syntactic requirement: The right-hand side of |> must be an explicit function call ending with parentheses ().