Struct NamedList 

pub struct NamedList {
    list: List,
    index: HashMap<String, usize>,
}

A named list with O(1) name-based element lookup.

Wraps a List and builds a HashMap<String, usize> index of element names on construction. Use this when you need to access multiple elements by name from the same list — each lookup is O(1) instead of O(n).

When to Use

Pattern	Type
Single named lookup	List::get_named is fine
Multiple named lookups	NamedList (O(n) build + O(1) per lookup)
Positional access only	List — no indexing overhead

Name Handling

• NA and empty-string names are excluded from the index
• If duplicate names exist, the last occurrence wins
• Positional access via get_index is always available

Fields

list: List

index: HashMap<String, usize>

Implementations

impl NamedList

pub fn as_data_frame(&self) -> Result<DataFrameView, DataFrameError>

Promote this named list to a DataFrameView.

Validates that all columns have equal length, then sets the class attribute to "data.frame" and adds compact integer row.names.

Errors

Returns DataFrameError::UnequalLengths if columns differ in length.

impl NamedList

pub fn new(list: List) -> Option<Self>

Build a NamedList from a List, indexing all non-empty, non-NA names.

Returns None if the list has no names attribute.

pub fn get<T>(&self, name: &str) -> Option<T>

where T: TryFromSexp<Error = SexpError>,

Get an element by name with O(1) lookup, converting to type T.

Returns None if the name is not found or conversion fails.

pub fn get_raw(&self, name: &str) -> Option<SEXP>

Get a raw SEXP element by name with O(1) lookup.

pub fn get_index<T>(&self, idx: isize) -> Option<T>

where T: TryFromSexp<Error = SexpError>,

Get element at 0-based index and convert to type T.

Falls through to List::get_index — no name lookup involved.

pub fn contains(&self, name: &str) -> bool

Check if a name exists in the index.

pub fn len(&self) -> isize

Number of elements in the list (including unnamed ones).

pub fn is_empty(&self) -> bool

Returns true if the list is empty.

pub fn named_len(&self) -> usize

Number of indexed (named) elements.

pub fn as_list(&self) -> List

Get the underlying List.

pub fn into_list(self) -> List

Consume and return the underlying List.

pub fn names(&self) -> impl Iterator<Item = &str>

Iterate over indexed names (unordered).

pub fn entries(&self) -> impl Iterator<Item = (&str, usize)>

Iterate over (name, position) pairs (unordered).

Trait Implementations

impl IntoR for NamedList

type Error = Infallible

The error type for fallible conversions.

fn try_into_sexp(self) -> Result<SEXP, Self::Error>

Try to convert this value to an R SEXP.

unsafe fn try_into_sexp_unchecked(self) -> Result<SEXP, Self::Error>

Try to convert to SEXP without thread safety checks.

fn into_sexp(self) -> SEXP

Convert this value to an R SEXP, panicking on error.

unsafe fn into_sexp_unchecked(self) -> SEXP

where Self: Sized,

Convert to SEXP without thread safety checks, panicking on error.

impl TryFromSexp for NamedList

type Error = SexpError

The error type returned when conversion fails.

fn try_from_sexp(sexp: SEXP) -> Result<Self, Self::Error>

Attempt to convert an R SEXP to this Rust type.

unsafe fn try_from_sexp_unchecked(sexp: SEXP) -> Result<Self, Self::Error>

Convert from SEXP without thread safety checks.