pryr

pryr

Tools for computing on the language.

Object Information

library(pryr)

# Object size
object_size(x)
object_size(x, y)  # Combined size

# Compare sizes
compare_size(x, y)

# Memory address
address(x)

# References to object
refs(x)

Memory Tracking

# Track memory changes
mem_used()

# Memory change from expression
mem_change(x <- 1:1e6)

# Track allocations
track_copy(x)

Object Types

# Type of object
otype(x)  # base, S3, S4, RC, R6

# Is object...
is_s3_generic(f)
is_s3_method(f)

# Function type
ftype(f)  # primitive, internal, closure, special

Environments

# Where is object defined
where("mean")

# Parent environments
parenvs(e)

# Environment as list
env2list(e)

Function Inspection

# Function body
body(f)

# Function arguments
fargs(f)

# Function environment
environment(f)

# Unenclose function
unenclose(f)

Promises

# Check if promise
is_promise(x)

# Promise info
promise_info(x)

Calls and Expressions

# Standardize call
standardise_call(quote(mean(x, na.rm = TRUE)))

# Modify call
modify_call(call, new_args)

# Call tree
call_tree(quote(f(g(x), h(y))))

Active Bindings

# Create active binding
make_active_binding("x", function() runif(1), .GlobalEnv)

# Check if active binding
is_active_binding("x")

Partial Application

# Partial function application
f <- function(x, y, z) x + y + z
g <- partial(f, x = 1)
g(y = 2, z = 3)  # Returns 6

# With dots
h <- partial(f, x = 1, .lazy = FALSE)

Composition

# Compose functions
f <- function(x) x + 1
g <- function(x) x * 2

fg <- compose(f, g)  # f(g(x))
fg(5)  # Returns 11

Substitution

# Substitute in expression
subs(x + y, list(x = 1))

# Substitute with quoting
subs_q(x + y, list(x = quote(a)))

Bytecode

# Check if bytecode compiled
is_bytecode(f)

# Disassemble bytecode
disassemble(f)

Performance

# Compare object sizes
object_size(1:1000)
object_size(as.numeric(1:1000))

# Memory efficient operations
# Use pryr to understand memory behavior
x <- 1:1e6
address(x)
x[1] <- 0L
address(x)  # Same address (modify in place)

y <- x
address(y)  # Same address (copy on modify)
y[1] <- 1L
address(y)  # Different address (copied)