Skip to content

Cherry pick Doctests for UnionBuilder and UnionArray. to active_release #618

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
alamb merged 1 commit into from
Jul 28, 2021
Merged

Cherry pick Doctests for UnionBuilder and UnionArray. to active_release #618

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
69 changes: 11 additions & 58 deletions arrow/src/array/array_union.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -15,64 +15,8 @@
// specific language governing permissions and limitations
// under the License.

//! Contains the `UnionArray` type.
//!
//! Each slot in a `UnionArray` can have a value chosen from a number of types. Each of the
//! possible types are named like the fields of a [`StructArray`](crate::array::StructArray).
//! A `UnionArray` can have two possible memory layouts, "dense" or "sparse". For more information
//! on please see the [specification](https://arrow.apache.org/docs/format/Columnar.html#union-layout).
//!
//! Builders are provided for `UnionArray`'s involving primitive types. `UnionArray`'s of nested
//! types are also supported but not via `UnionBuilder`, see the tests for examples.
//!
//! # Example: Dense Memory Layout
//!
//! ```
//! use arrow::array::UnionBuilder;
//! use arrow::datatypes::{Float64Type, Int32Type};
//!
//! # fn main() -> arrow::error::Result<()> {
//! let mut builder = UnionBuilder::new_dense(3);
//! builder.append::<Int32Type>("a", 1).unwrap();
//! builder.append::<Float64Type>("b", 3.0).unwrap();
//! builder.append::<Int32Type>("a", 4).unwrap();
//! let union = builder.build().unwrap();
//!
//! assert_eq!(union.type_id(0), 0_i8);
//! assert_eq!(union.type_id(1), 1_i8);
//! assert_eq!(union.type_id(2), 0_i8);
//!
//! assert_eq!(union.value_offset(0), 0_i32);
//! assert_eq!(union.value_offset(1), 0_i32);
//! assert_eq!(union.value_offset(2), 1_i32);
//!
//! # Ok(())
//! # }
//! ```
//!
//! # Example: Sparse Memory Layout
//! ```
//! use arrow::array::UnionBuilder;
//! use arrow::datatypes::{Float64Type, Int32Type};
//!
//! # fn main() -> arrow::error::Result<()> {
//! let mut builder = UnionBuilder::new_sparse(3);
//! builder.append::<Int32Type>("a", 1).unwrap();
//! builder.append::<Float64Type>("b", 3.0).unwrap();
//! builder.append::<Int32Type>("a", 4).unwrap();
//! let union = builder.build().unwrap();
//!
//! assert_eq!(union.type_id(0), 0_i8);
//! assert_eq!(union.type_id(1), 1_i8);
//! assert_eq!(union.type_id(2), 0_i8);
//!
//! assert_eq!(union.value_offset(0), 0_i32);
//! assert_eq!(union.value_offset(1), 1_i32);
//! assert_eq!(union.value_offset(2), 2_i32);
//!
//! # Ok(())
//! # }
//! ```
/// Contains the `UnionArray` type.
///
use crate::array::{data::count_nulls, make_array, Array, ArrayData, ArrayRef};
use crate::buffer::Buffer;
use crate::datatypes::*;
Expand All @@ -83,6 +27,15 @@ use std::any::Any;
use std::mem::size_of;

/// An Array that can represent slots of varying types.
///
/// Each slot in a `UnionArray` can have a value chosen from a number of types. Each of the
/// possible types are named like the fields of a [`StructArray`](crate::array::StructArray).
/// A `UnionArray` can have two possible memory layouts, "dense" or "sparse". For more information
/// on please see the [specification](https://arrow.apache.org/docs/format/Columnar.html#union-layout).
///
/// [`UnionBuilder`]can be used to create `UnionArray`'s of primitive types. `UnionArray`'s of nested
/// types are also supported but not via `UnionBuilder`, see the tests for examples.
///
pub struct UnionArray {
data: ArrayData,
boxed_fields: Vec<ArrayRef>,
Expand Down
41 changes: 41 additions & 0 deletions arrow/src/array/builder.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1706,6 +1706,47 @@ impl FieldData {
}

/// Builder type for creating a new `UnionArray`.
///
/// Example: **Dense Memory Layout**
///
/// ```
/// use arrow::array::UnionBuilder;
/// use arrow::datatypes::{Float64Type, Int32Type};
///
/// let mut builder = UnionBuilder::new_dense(3);
/// builder.append::<Int32Type>("a", 1).unwrap();
/// builder.append::<Float64Type>("b", 3.0).unwrap();
/// builder.append::<Int32Type>("a", 4).unwrap();
/// let union = builder.build().unwrap();
///
/// assert_eq!(union.type_id(0), 0_i8);
/// assert_eq!(union.type_id(1), 1_i8);
/// assert_eq!(union.type_id(2), 0_i8);
///
/// assert_eq!(union.value_offset(0), 0_i32);
/// assert_eq!(union.value_offset(1), 0_i32);
/// assert_eq!(union.value_offset(2), 1_i32);
/// ```
///
/// Example: **Sparse Memory Layout**
/// ```
/// use arrow::array::UnionBuilder;
/// use arrow::datatypes::{Float64Type, Int32Type};
///
/// let mut builder = UnionBuilder::new_sparse(3);
/// builder.append::<Int32Type>("a", 1).unwrap();
/// builder.append::<Float64Type>("b", 3.0).unwrap();
/// builder.append::<Int32Type>("a", 4).unwrap();
/// let union = builder.build().unwrap();
///
/// assert_eq!(union.type_id(0), 0_i8);
/// assert_eq!(union.type_id(1), 1_i8);
/// assert_eq!(union.type_id(2), 0_i8);
///
/// assert_eq!(union.value_offset(0), 0_i32);
/// assert_eq!(union.value_offset(1), 1_i32);
/// assert_eq!(union.value_offset(2), 2_i32);
/// ```
#[derive(Debug)]
pub struct UnionBuilder {
/// The current number of slots in the array
Expand Down