doBy (version 4.6.27)

pick_elements: Extract (pick) elements without using brackets

Description

Extract (pick) elements without using brackets so that elements can be picked out as part of a pipe workflow.

Usage

pick1(x, which)
pick2(x, which)

Value

• pick1() returns a subset of x.

• pick2() returns a single element from x.

Arguments

x

A list, data frame, or vector.

which

The index or name of the element(s) to extract.

Details

These two helper functions extract elements from lists, data frames, or vectors. They are simple wrappers for the standard bracket operators in R:

• pick1() uses single brackets ([) and returns a subset.

• pick2() uses double brackets ([[) and returns the element itself.

These are safer and more flexible than $, especially when used with the base R pipe (|>) or in functional programming.

Examples

lst <- list(a = 1:3, b = 4:6)

# Without pipe
pick1(lst, "a")      # List with one element
pick2(lst, "a")      # Just the vector 1:3

# With base R pipe
lst |> pick1("a")
lst |> pick2("a")

df <- data.frame(x = 1:5, y = letters[1:5])

df |> pick1("y")     # Returns a data frame with column 'y'
df |> pick2("y")     # Returns column 'y' as a character vector