narrow 0.1.0

A Rust implementation of Apache Arrow
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135

# Narrow

[![crates.io](https://img.shields.io/crates/v/narrow.svg)](https://crates.io/crates/narrow)
[![docs.rs](https://docs.rs/narrow/badge.svg)](https://docs.rs/narrow)

A Rust implementation of [Apache Arrow](https://arrow.apache.org).

## Docs

- [Docs (release)](https://docs.rs/narrow)
- [Docs (main)](https://mbrobbel.github.io/narrow/narrow/index.html)

## Progress

- [x] Buffer
- [x] Bitmap
- [x] Nullable
- [x] Validity
- [x] Offset
- [x] Array
  - [x] Fixed-size primitive
  - [x] Boolean
  - [x] Variable-size binary
    - [x] String array
  - [x] Variable-size list
  - [x] Fixed-size list
  - [x] Struct
  - [x] Union
    - [x] Dense
    - [x] Sparse
  - [x] Null
  - [x] Dictionary
- [ ] Logical types
- [ ] Schema
- [ ] RecordBatch
- [ ] DictionaryBatch
- [ ] Table
- [ ] IPC
  - [ ] Streaming
  - [ ] File
- [ ] Flight
- [ ] Documentation
- [ ] Benchmarks

## Minimum supported Rust version

The minimum supported Rust version is 1.54.

## Example

### Struct array

```rust
use narrow::{Array, BooleanArray, Float32Array, StructArray, Uint8Array};

#[derive(Array, Copy, Clone, Debug, PartialEq)]
pub struct Person {
    name: String,
    age: u8,
    happy: bool,
    distance: Option<f32>,
}

let persons = vec![
    Person {
        name: "A".to_string(),
        age: 20,
        happy: true,
        distance: Some(1.5),
    },
    Person {
        name: "B".to_string(),
        age: 22,
        happy: true,
        distance: None,
    },
];

// Convert array of structs to struct of arrays.
let persons_array: StructArray<Person, false> = persons.clone().into_iter().collect();
assert_eq!(persons_array.len(), 2);

// To sum the ages we only need to read the `age` array.
let age_array: &Uint8Array<false> = &persons_array.age;
assert_eq!(age_array.into_iter().sum::<u8>(), 42);

// Make sure everyone is happy.
let happy_array: &BooleanArray<false> = &persons_array.happy;
assert!(happy_array.into_iter().all(|bool| bool));

// The const generic bool in array types indicates nullability of the
// values in that array.
let distance_array: &Float32Array<true> = &persons_array.distance;
assert_eq!(distance_array.null_count(), 1);

// Convert struct of arrays back to array of structs
assert_eq!(persons_array.into_iter().collect::<Vec<_>>(), persons);
```

### Union array

```rust
use narrow::{Array, UnionArray};

#[derive(Array, Copy, Clone, Debug, PartialEq)]
pub enum Either {
    This(bool),
    That(Option<u32>)
}

let input = vec![
    Either::This(false),
    Either::This(true),
    Either::That(Some(1234)),
    Either::That(None),
    Either::This(true)
];

let array: UnionArray<Either, true> = input.iter().copied().collect();

assert_eq!(array.len(), 5);
assert_eq!(array.child().This.len(), 3);
assert_eq!(array.child().That.len(), 2);
assert_eq!(array.child().That.null_count(), 1);

assert_eq!(array.into_iter().collect::<Vec<Either>>(), input);
```
  
## License

Licensed under either of [Apache License, Version 2.0](LICENSE-APACHE) or [MIT license](LICENSE-MIT) at your option.

## Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.