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Added the ability to open json lines dataframes with polars lazy json lines reader. (#13167)

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The `--lazy` flag will now use the polars' LazyJsonLinesReader when
opening a json lines file with `polars open`
This commit is contained in:
Jack Wright 2024-06-20 10:55:49 -07:00 committed by GitHub
parent c09a8a5ec9
commit 7d2d573eb8
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GPG Key ID: B5690EEEBB952194
1 changed files with 48 additions and 30 deletions
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26
crates/nu_plugin_polars/src/dataframe/eager/open.rs
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@ -19,9 +19,12 @@ use std::{
sync::Arc,
};
use polars::prelude::{
CsvEncoding, IpcReader, JsonFormat, JsonReader, LazyCsvReader, LazyFileListReader, LazyFrame,
ParquetReader, ScanArgsIpc, ScanArgsParquet, SerReader,
use polars::{
lazy::frame::LazyJsonLineReader,
prelude::{
CsvEncoding, IpcReader, JsonFormat, JsonReader, LazyCsvReader, LazyFileListReader,
LazyFrame, ParquetReader, ScanArgsIpc, ScanArgsParquet, SerReader,
},
};
use polars_io::{
@ -375,6 +378,21 @@ fn from_jsonl(
.get_flag("schema")?
.map(|schema| NuSchema::try_from(&schema))
.transpose()?;
if call.has_flag("lazy")? {
let df = LazyJsonLineReader::new(file_path)
.with_infer_schema_length(infer_schema)
.with_schema(maybe_schema.map(|s| s.into()))
.finish()
.map_err(|e| ShellError::GenericError {
error: format!("Json lines reader error: {e}"),
msg: "".into(),
span: Some(call.head),
help: None,
inner: vec![],
})?;
let df = NuLazyFrame::new(false, df);
df.cache_and_to_value(plugin, engine, call.head)
} else {
let file = File::open(file_path).map_err(|e| ShellError::GenericError {
error: "Error opening file".into(),
msg: e.to_string(),
@ -382,7 +400,6 @@ fn from_jsonl(
help: None,
inner: vec![],
})?;
let buf_reader = BufReader::new(file);
let reader = JsonReader::new(buf_reader)
.with_json_format(JsonFormat::JsonLines)
@ -406,6 +423,7 @@ fn from_jsonl(
df.cache_and_to_value(plugin, engine, call.head)
}
}
fn from_csv(
plugin: &PolarsPlugin,