我可以创建类型为“UTF8”的列,如下所示
let schema = Arc::new(Schema::new(vec![
Field::new("id", DataType::Int32, false),
Field::new("payload", DataType::Utf8, false),
]));
let vec_of_strings: Vec<String> = vec!["one".to_string(), "two".to_string()];
let batch = RecordBatch::try_new(
schema,
vec![
Arc::new(Int32Array::from_slice([1, 2])),
Arc::new(StringArray::from(vec_of_strings)),
],
)?;
ctx.register_batch("demo", batch)?;
对此执行查询,如下所示
let df = ctx.sql(r
SELECT *
from demo
"#).await?;
给出了预期结果
+----+---------+
| id | payload |
+----+---------+
| 1 | one |
| 2 | two |
+----+---------+
现在我有一个用例,其中有效负载应该是一个数组。所以像这样的事情
+----+---------+
| id | payload |
+----+---------+
| 1 | [piano, guitar, drums] |
| 2 | [violin, piano] |
+----+---------+
我该怎么办?
更改
vec_of_strings
到
vec_of_vecs
失败。我是认真的
let vec_of_vecs: Vec<Vec<String>> = vec![
vec!["piano".to_string(), "guitar".to_string(), "drums".to_string()],
vec!["violin".to_string(), "guitar".to_string()]
];
当用于创建这样的批时
let batch = RecordBatch::try_new(
schema,
vec![
Arc::new(Int32Array::from_slice([1, 2])),
Arc::new(StringArray::from(vec_of_vecs)),
],
)?;
编译失败,出现错误
|
80 | Arc::new(StringArray::from(vec_of_vecs)),
|
| |
| required by a bound introduced by this call
|
= help: the following other types implement trait `From<T>`:
<GenericByteArray<GenericBinaryType<OffsetSize>> as From<GenericByteArray<GenericStringType<OffsetSize>>>>
<GenericByteArray<GenericBinaryType<OffsetSize>> as From<Vec<&[u8]>>>
<GenericByteArray<GenericBinaryType<OffsetSize>> as From<Vec<Option<&[u8]>>>>
<GenericByteArray<GenericBinaryType<T>> as From<GenericListArray<T>>>
<GenericByteArray<GenericStringType<OffsetSize>> as From<GenericByteArray<GenericBinaryType<OffsetSize>>>>
<GenericByteArray<GenericStringType<OffsetSize>> as From<GenericListArray<OffsetSize>>>
<GenericByteArray<GenericStringType<OffsetSize>> as From<Vec<&str>>>
<GenericByteArray<GenericStringType<OffsetSize>> as From<Vec<Option<&str>>>>
and 3 others
你知道我该如何实现上述目标吗?