11_map/
11_map.rs

1use std::collections::BTreeMap;
2
3use arrow_array::Array;
4use typed_arrow::{Map, OrderedMap, Record, bridge::ArrowBinding};
5
6#[derive(Record)]
7struct Row {
8    id: i32,
9    tags: Map<String, i32>,
10    notes: Option<Map<String, Option<String>>>, // nullable map with nullable values
11}
12
13fn main() {
14    // Standalone Map column
15    let mut b = <Map<String, i32> as ArrowBinding>::new_builder(0);
16    <Map<String, i32> as ArrowBinding>::append_value(
17        &mut b,
18        &Map::new(vec![("a".to_string(), 1), ("b".to_string(), 2)]),
19    );
20    <Map<String, i32> as ArrowBinding>::append_null(&mut b);
21    let a = <Map<String, i32> as ArrowBinding>::finish(b);
22    println!(
23        "standalone map rows={}, entries={}",
24        a.len(),
25        a.entries().len()
26    );
27
28    // Sorted keys example (keys_sorted = true)
29    let dt_sorted = <Map<String, i32, true> as ArrowBinding>::data_type();
30    println!("sorted map datatype = {dt_sorted:?}");
31
32    // OrderedMap using BTreeMap row layout
33    let mut ord = BTreeMap::new();
34    ord.insert("b".to_string(), 2);
35    ord.insert("a".to_string(), 1);
36    let mut ob = <OrderedMap<String, i32> as ArrowBinding>::new_builder(0);
37    <OrderedMap<String, i32> as ArrowBinding>::append_value(&mut ob, &OrderedMap::new(ord));
38    let oa = <OrderedMap<String, i32> as ArrowBinding>::finish(ob);
39    println!("ordered map entries={}", oa.entries().len());
40
41    // In a Record
42    let rows = vec![
43        Row {
44            id: 1,
45            tags: Map::new(vec![("x".to_string(), 10)]),
46            notes: Some(Map::new(vec![
47                ("hello".to_string(), Some("world".to_string())),
48                ("empty".to_string(), None),
49            ])),
50        },
51        Row {
52            id: 2,
53            tags: Map::new(vec![]),
54            notes: None,
55        },
56    ];
57    let mut rb = <Row as typed_arrow::schema::BuildRows>::new_builders(rows.len());
58    rb.append_rows(rows);
59    let arrays = rb.finish();
60    let batch = arrays.into_record_batch();
61    println!(
62        "record rows={}, fields={}",
63        batch.num_rows(),
64        batch.schema().fields().len()
65    );
66}
11_map/11_map.rs

11_map/
11_map.rs
