nushell/crates/nu_plugin_polars/src/dataframe/series/n_unique.rs
Stefan Holderbach be6137d136
Fix clippy::wrong_self_convention in polars plugin (#12737)
Expected `into_` for `fn(self) -> T`
2024-05-02 19:31:51 +02:00

133 lines
3.9 KiB
Rust

use crate::{
values::{cant_convert_err, CustomValueSupport, PolarsPluginObject, PolarsPluginType},
PolarsPlugin,
};
use super::super::values::{Column, NuDataFrame, NuExpression};
use nu_plugin::{EngineInterface, EvaluatedCall, PluginCommand};
use nu_protocol::{
Category, Example, LabeledError, PipelineData, ShellError, Signature, Span, Type, Value,
};
#[derive(Clone)]
pub struct NUnique;
impl PluginCommand for NUnique {
type Plugin = PolarsPlugin;
fn name(&self) -> &str {
"polars n-unique"
}
fn usage(&self) -> &str {
"Counts unique values."
}
fn signature(&self) -> Signature {
Signature::build(self.name())
.input_output_types(vec![
(
Type::Custom("expression".into()),
Type::Custom("expression".into()),
),
(
Type::Custom("dataframe".into()),
Type::Custom("dataframe".into()),
),
])
.category(Category::Custom("dataframe".into()))
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "Counts unique values",
example: "[1 1 2 2 3 3 4] | polars into-df | polars n-unique",
result: Some(
NuDataFrame::try_from_columns(
vec![Column::new(
"count_unique".to_string(),
vec![Value::test_int(4)],
)],
None,
)
.expect("simple df for test should not fail")
.into_value(Span::test_data()),
),
},
Example {
description: "Creates a is n-unique expression from a column",
example: "polars col a | polars n-unique",
result: None,
},
]
}
fn run(
&self,
plugin: &Self::Plugin,
engine: &EngineInterface,
call: &EvaluatedCall,
input: PipelineData,
) -> Result<PipelineData, LabeledError> {
let value = input.into_value(call.head);
match PolarsPluginObject::try_from_value(plugin, &value)? {
PolarsPluginObject::NuDataFrame(df) => command(plugin, engine, call, df),
PolarsPluginObject::NuLazyFrame(lazy) => {
command(plugin, engine, call, lazy.collect(call.head)?)
}
PolarsPluginObject::NuExpression(expr) => {
let expr: NuExpression = expr.into_polars().n_unique().into();
expr.to_pipeline_data(plugin, engine, call.head)
}
_ => Err(cant_convert_err(
&value,
&[
PolarsPluginType::NuDataFrame,
PolarsPluginType::NuLazyFrame,
PolarsPluginType::NuExpression,
],
)),
}
.map_err(LabeledError::from)
}
}
fn command(
plugin: &PolarsPlugin,
engine: &EngineInterface,
call: &EvaluatedCall,
df: NuDataFrame,
) -> Result<PipelineData, ShellError> {
let res = df
.as_series(call.head)?
.n_unique()
.map_err(|e| ShellError::GenericError {
error: "Error counting unique values".into(),
msg: e.to_string(),
span: Some(call.head),
help: None,
inner: vec![],
})?;
let value = Value::int(res as i64, call.head);
let df = NuDataFrame::try_from_columns(
vec![Column::new("count_unique".to_string(), vec![value])],
None,
)?;
df.to_pipeline_data(plugin, engine, call.head)
}
#[cfg(test)]
mod test {
use super::*;
use crate::test::test_polars_plugin_command;
#[test]
fn test_examples() -> Result<(), ShellError> {
test_polars_plugin_command(&NUnique)
}
}