forked from extern/nushell
84 lines
2.2 KiB
Rust
84 lines
2.2 KiB
Rust
use super::super::values::{Column, NuDataFrame};
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use nu_protocol::{
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ast::Call,
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engine::{Command, EngineState, Stack},
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Category, Example, PipelineData, ShellError, Signature, Span, Value,
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};
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use polars::prelude::IntoSeries;
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#[derive(Clone)]
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pub struct Unique;
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impl Command for Unique {
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fn name(&self) -> &str {
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"dfr unique"
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}
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fn usage(&self) -> &str {
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"Returns unique values from a series"
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}
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fn signature(&self) -> Signature {
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Signature::build(self.name()).category(Category::Custom("dataframe".into()))
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}
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fn examples(&self) -> Vec<Example> {
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vec![Example {
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description: "Returns unique values from a series",
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example: "[2 2 2 2 2] | dfr to-df | dfr unique",
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result: Some(
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NuDataFrame::try_from_columns(vec![Column::new(
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"0".to_string(),
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vec![Value::test_int(2)],
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)])
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.expect("simple df for test should not fail")
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.into_value(Span::test_data()),
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),
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}]
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}
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fn run(
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&self,
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engine_state: &EngineState,
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stack: &mut Stack,
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call: &Call,
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input: PipelineData,
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) -> Result<PipelineData, ShellError> {
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command(engine_state, stack, call, input)
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}
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}
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fn command(
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_engine_state: &EngineState,
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_stack: &mut Stack,
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call: &Call,
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input: PipelineData,
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) -> Result<PipelineData, ShellError> {
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let df = NuDataFrame::try_from_pipeline(input, call.head)?;
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let series = df.as_series(call.head)?;
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let res = series.unique().map_err(|e| {
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ShellError::SpannedLabeledErrorHelp(
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"Error calculating unique values".into(),
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e.to_string(),
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call.head,
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"The str-slice command can only be used with string columns".into(),
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)
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})?;
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NuDataFrame::try_from_series(vec![res.into_series()], call.head)
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.map(|df| PipelineData::Value(NuDataFrame::into_value(df, call.head), None))
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}
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#[cfg(test)]
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mod test {
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use super::super::super::test_dataframe::test_dataframe;
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use super::*;
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#[test]
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fn test_examples() {
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test_dataframe(vec![Box::new(Unique {})])
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}
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}
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