is_copyable: Is an object copyable?

In hadley/rlang: Functions for Base Types and Core R and 'Tidyverse' Features

Is an object copyable?

Description

When an object is modified, R generally copies it (sometimes lazily) to enforce value semantics. However, some internal types are uncopyable. If you try to copy them, either with ⁠<-⁠ or by argument passing, you actually create references to the original object rather than actual copies. Modifying these references can thus have far reaching side effects.

Usage

is_copyable(x)

Arguments

x	An object to test.

Examples

# Let's add attributes with structure() to uncopyable types. Since
# they are not copied, the attributes are changed in place:
env <- env()
structure(env, foo = "bar")
env

# These objects that can only be changed with side effect are not
# copyable:
is_copyable(env)

structure(base::list, foo = "bar")
str(base::list)

hadley/rlang documentation built on Nov. 1, 2024, 4 p.m.