nushell/crates/nu-command/src/dataframe/series/masks/not.rs

use super::super::super::values::{Column, NuDataFrame};
use crate::dataframe::values::NuExpression;
use nu_protocol::{
    ast::Call,
    engine::{Command, EngineState, Stack},
    Category, Example, PipelineData, ShellError, Signature, Span, Value,
};
use polars::prelude::IntoSeries;

use std::ops::Not;

#[derive(Clone)]
pub struct NotSeries;

impl Command for NotSeries {
    fn name(&self) -> &str {
        "dfr not"
    }

    fn usage(&self) -> &str {
        "Inverts boolean mask or creates a not expression"
    }

    fn signature(&self) -> Signature {
        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
    }

    fn examples(&self) -> Vec<Example> {
        vec![
            Example {
                description: "Inverts boolean mask",
                example: "[true false true] | dfr to-df | dfr not",
                result: Some(
                    NuDataFrame::try_from_columns(vec![Column::new(
                        "0".to_string(),
                        vec![
                            Value::test_bool(false),
                            Value::test_bool(true),
                            Value::test_bool(false),
                        ],
                    )])
                    .expect("simple df for test should not fail")
                    .into_value(Span::test_data()),
                ),
            },
            Example {
                description: "Creates a not expression from a column",
                example: "dfr col a | dfr not",
                result: None,
            },
        ]
    }

    fn run(
        &self,
        engine_state: &EngineState,
        stack: &mut Stack,
        call: &Call,
        input: PipelineData,
    ) -> Result<PipelineData, ShellError> {
        let value = input.into_value(call.head);

        if NuExpression::can_downcast(&value) {
            let expr = NuExpression::try_from_value(value)?;
            let expr: NuExpression = expr.into_polars().is_null().into();

            Ok(PipelineData::Value(
                NuExpression::into_value(expr, call.head),
                None,
            ))
        } else if NuDataFrame::can_downcast(&value) {
            let df = NuDataFrame::try_from_value(value)?;
            command(engine_state, stack, call, df)
        } else {
            Err(ShellError::CantConvert(
                "expression or query".into(),
                value.get_type().to_string(),
                value.span()?,
                None,
            ))
        }
    }
}

fn command(
    _engine_state: &EngineState,
    _stack: &mut Stack,
    call: &Call,
    df: NuDataFrame,
) -> Result<PipelineData, ShellError> {
    let series = df.as_series(call.head)?;

    let bool = series.bool().map_err(|e| {
        ShellError::GenericError(
            "Error inverting mask".into(),
            e.to_string(),
            Some(call.head),
            None,
            Vec::new(),
        )
    })?;

    let res = bool.not();

    NuDataFrame::try_from_series(vec![res.into_series()], call.head)
        .map(|df| PipelineData::Value(NuDataFrame::into_value(df, call.head), None))
}

#[cfg(test)]
mod test {
    use super::super::super::super::test_dataframe::test_dataframe;
    use super::*;

    #[test]
    fn test_examples() {
        test_dataframe(vec![Box::new(NotSeries {})])
    }
}