Module dataframe 

R data.frame views, rooted Rust-built handles, and conversion traits.

DataFrame is a cheap Copy view over a validated data.frame SEXP; BuiltDataFrame is the owned, GC-rooted handle returned by every Rust-side constructor. Together they serve every direction:

• build (Rust → R): IntoDataFrame::into_dataframe / into_dataframe_par (feature = "rayon"),
• read (R → Rust): DataFrame::column / FromDataFrame::from_dataframe,
• edit (post-assembly): DataFrame::rename / DataFrame::drop / DataFrame::select / … — the new-frame producers return an owned, GC-rooted BuiltDataFrame (#1247), so constructor → edit chains stay rooted at every link.

The trait family mirrors the crate’s existing IntoR / TryFromSexp pair, specialised to the data-frame SEXP:

use miniextendr_api::dataframe::{DataFrame, IntoDataFrame, FromDataFrame};

// Rust → R (returns an owned, GC-rooted `BuiltDataFrame` that `Deref`s to `DataFrame`)
let df = rows.into_dataframe()?;          // sequential
let df = rows.into_dataframe_par()?;      // parallel (feature = "rayon")

// R → Rust
let rows: Vec<Row> = Vec::<Row>::from_dataframe(&df)?;

DataFrame implements TryFromSexp and IntoR, so caller-rooted views slot into #[miniextendr] argument and return conversion. BuiltDataFrame also implements IntoR; return rooted Rust-side constructor results directly.

One error contract

Every conversion failure surfaces as DataFrameError. The serde column assembler’s internal RSerdeError is bridged via From<RSerdeError>; the parallel R→Rust reader reports through DataFrameError rather than a bare String.

Re-exports

pub use group::GroupDeclaration;

pub use group::GroupKey;

pub use group::GroupedDataFrame;

pub use group::RealKey;

pub use group::group_rows;

pub use shape::DataFrameShape;

pub use shape::SplitResults;

Modules

group

Group-level iteration over a DataFrame key column.

shape 🔒

DataFrameShape: the owned, GC-rooted return shape of the data.frame split verbs.

Structs

BuiltDataFrame

An owned, GC-rooted data.frame built on the Rust side.

DataFrame

A cheap Copy view over a validated R data.frame.

Enums

DataFrameError

Error returned by any DataFrame construction, read, or conversion path.

Constants

CORRUPT_GROUPS_HINT 🔒

The fix that the corrupt-groups errors (DataFrameError::GroupsNotDataFrame, DataFrameError::MissingGroupRows, DataFrameError::BadGroupRows) append to their message.

STALE_GROUPS_HINT 🔒

The cause and the fix that the stale-.rows errors (DataFrameError::GroupIndexOutOfRange, DataFrameError::GroupRowUncovered, DataFrameError::GroupRowDuplicated) append to their message.

Traits

ColumnSource 👻

Internal engine that turns a value into a data.frame-shaped List.

ColumnarFrame

Rust rows ↔ the pure-Rust columnar companion generated by #[derive(DataFrameRow)].

DataFrameRowConvert 👻

Row → DataFrame conversion glue emitted by #[derive(DataFrameRow)] on the row type.

DataFrameRowSplit 👻

Row → split-representation glue emitted by #[derive(DataFrameRow)] on enum row types.

FromDataFrame

R data.frame → Rust data. The data-frame analogue of TryFromSexp.

IntoDataFrame

Rust data → R data.frame. The data-frame analogue of IntoR.

IntoDataFrameSplit

Enum rows → variant-partitioned R data.frames. The split-representation sibling of IntoDataFrame.

Functions

col_name 🔒 ^⚠

Read the i-th column name from a STRSXP names vector.

column_named 🔒 ^⚠

The first column of the data.frame list frame named name.

copy_frame_attrs 🔒 ^⚠

Copy the frame attributes of from onto the new frame to.

extract_nrow 🔒

Extract nrow from R’s row.names attribute.

grouping_columns_kept 🔒 ^⚠

Whether every grouping variable of the grouped frame from (the columns its groups attribute names, .rows aside) is a column of to that is the same SEXP as in from. false when groups is not a data frame.

no_reader_error 🔒

Error returned by Vec::<Row>::from_dataframe when the row shape has no R→Rust reader.

nrow_from_first_column 🔒

Fall back: extract nrow from the length of the first column.

select_column_rows 🔒 ^⚠

Row-subset one data.frame column at the 0-based rows idx (see DataFrame::select_rows for the per-kind rules). Returns it protected.

select_frame_rows 🔒 ^⚠

The body of DataFrame::select_rows: row-subset the data.frame VECSXP frame at the 0-based rows idx. Shared with packed data.frame columns.

ungroup_frame 🔒 ^⚠

Remove dplyr’s grouping from the frame to: its groups attribute and the grouped_df / rowwise_df entries of its class.

validate_equal_lengths 🔒

Validate that all columns in a NamedList have equal length, returning the common length.