edoardo-coronado opened a new issue, #4510:
URL: https://github.com/apache/arrow-rs/issues/4510
I have written the following code in rust to create a parquet file with two
columns using parquet 43.0.0:
fn main()
{
let vector_length: usize = 4;
let mut vector1: Vec<i32> = Vec::with_capacity(vector_length);
let mut vector2: Vec<i64> = Vec::with_capacity(vector_length);
let mut vector3: Vec<f32> = Vec::with_capacity(vector_length);
let mut vector4: Vec<f64> = Vec::with_capacity(vector_length);
let mut rng = rand::thread_rng();
for _ in 0..vector_length
{
let random_number_i32: i32 = rng.gen();
let random_number_i64: i64 = rng.gen();
vector1.push(random_number_i32);
vector2.push(random_number_i64);
}
let path:&Path = Path::new("./output.parquet");
let file = fs::File::create(&path).unwrap();
let message_type:&str = "message schema {\
REQUIRED INT32 col_i32;\
REQUIRED INT64 col_i64;\
let schema = Arc::new(parse_message_type(message_type).unwrap());
let props = Arc::new(WriterProperties::builder().build());
let mut writer = SerializedFileWriter::new(file, schema, props).unwrap();
let mut row_group_writer = writer.next_row_group().unwrap();
if let Some(mut col_writer) = row_group_writer.next_column().unwrap()
{
col_writer.typed::<Int32Type>()
.write_batch(&vector1, None, None)
.unwrap();
col_writer.close().unwrap()
}
if let Some(mut col_writer) = row_group_writer.next_column().unwrap()
{
col_writer.typed::<Int64Type>()
.write_batch(&vector2, None, None)
.unwrap();
col_writer.close().unwrap()
}
row_group_writer.close().unwrap();
writer.close().unwrap();
}
Despite it is working, I want to replace the two "if" blocks with while loop
and a match instruction like this:
while let Some(mut col_writer) = row_group_writer.next_column().unwrap()
{
match col_writer
{
ColumnWriter::Int32ColumnWriter(ref mut typed) =>
{typed.write_batch(&vector1, None, None).unwrap();}
ColumnWriter::Int64ColumnWriter(ref mut typed) =>
{typed.write_batch(&vector2, None, None).unwrap();}
_ => {}
}
}
And I get the following error:
error[E0308]: mismatched types
--> src/main.rs:61:13
|
59 | match col_writer
| ---------- this expression has type
`SerializedColumnWriter<'_>`
60 | {
61 | ColumnWriter::Int32ColumnWriter(ref mut typed) =>
{typed.write_batch(&vector1, None, None).unwrap();}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected
`SerializedColumnWriter<'_>`, found `ColumnWriter<'_>`
|
help: you might have meant to use field `inner` whose type is
`ColumnWriter<'_>`
|
59 | match col_writer.inner
|
I tried to solve it by invoking the inner property, but then I get a second
error:
error[E0616]: field `inner` of struct `SerializedColumnWriter` is private
--> src/main.rs:59:26
|
59 | match col_writer.inner
| ^^^^^ private field
Inner is a private property, then my question how can I check and match the
type of a SerializedColumnWriter in order to chose different writing
instructions. I know that this ColumnWriter::Int32ColumnWriter(ref mut typed)
worked with parquet 4.2.0 according to this post in StackOverflow:
https://stackoverflow.com/questions/67900928/writing-a-vec-of-rows-to-a-parquet-file
.
I greatly appreciate your help,
Regards
Edoardo
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