nu_plugin_polars 0.113.0

Nushell dataframe plugin commands based on polars.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128

use crate::PolarsPlugin;
use crate::values::{Column, CustomValueSupport, NuDataFrame, PolarsPluginType};

use nu_plugin::{EngineInterface, EvaluatedCall, PluginCommand};
use nu_protocol::{
    Category, Example, LabeledError, PipelineData, ShellError, Signature, Span, Value,
    shell_error::generic::GenericError,
};

#[derive(Clone)]
pub struct AllTrue;

impl PluginCommand for AllTrue {
    type Plugin = PolarsPlugin;

    fn name(&self) -> &str {
        "polars all-true"
    }

    fn description(&self) -> &str {
        "Returns true if all values are true."
    }

    fn signature(&self) -> Signature {
        Signature::build(self.name())
            .input_output_types(vec![
                (
                    PolarsPluginType::NuDataFrame.into(),
                    PolarsPluginType::NuDataFrame.into(),
                ),
                (
                    PolarsPluginType::NuLazyFrame.into(),
                    PolarsPluginType::NuLazyFrame.into(),
                ),
            ])
            .category(Category::Custom("dataframe".into()))
    }

    fn examples(&self) -> Vec<Example<'_>> {
        vec![
            Example {
                description: "Returns true if all values are true",
                example: "[true true true] | polars into-df | polars all-true",
                result: Some(
                    NuDataFrame::try_from_columns(
                        vec![Column::new(
                            "all_true".to_string(),
                            vec![Value::test_bool(true)],
                        )],
                        None,
                        Span::test_data(),
                    )
                    .expect("simple df for test should not fail")
                    .into_value(Span::test_data()),
                ),
            },
            Example {
                description: "Checks the result from a comparison",
                example: r#"let s = ([5 6 2 8] | polars into-df);
    let res = ($s > 9);
    $res | polars all-true"#,
                result: Some(
                    NuDataFrame::try_from_columns(
                        vec![Column::new(
                            "all_true".to_string(),
                            vec![Value::test_bool(false)],
                        )],
                        None,
                        Span::test_data(),
                    )
                    .expect("simple df for test should not fail")
                    .into_value(Span::test_data()),
                ),
            },
        ]
    }

    fn run(
        &self,
        plugin: &Self::Plugin,
        engine: &EngineInterface,
        call: &EvaluatedCall,
        mut input: PipelineData,
    ) -> Result<PipelineData, LabeledError> {
        let metadata = input.take_metadata();
        command(plugin, engine, call, input)
            .map_err(LabeledError::from)
            .map(|pd| pd.set_metadata(metadata))
    }
}

fn command(
    plugin: &PolarsPlugin,
    engine: &EngineInterface,
    call: &EvaluatedCall,
    input: PipelineData,
) -> Result<PipelineData, ShellError> {
    let df = NuDataFrame::try_from_pipeline_coerce(plugin, input, call.head)?;

    let series = df.as_series(call.head)?;
    let bool = series.bool().map_err(|_| {
        ShellError::Generic(GenericError::new(
            "Error converting to bool",
            "all-false only works with series of type bool",
            call.head,
        ))
    })?;

    let value = Value::bool(bool.all(), call.head);

    let df = NuDataFrame::try_from_columns(
        vec![Column::new("all_true".to_string(), vec![value])],
        None,
        call.head,
    )?;
    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(&AllTrue)
    }
}