nu-command 0.75.0

Nushell's built-in commands
Documentation 
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
129
130
131
132
133
134
135
136
137
138
139
140
141

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

#[derive(Clone)]
pub struct Dummies;

impl Command for Dummies {
    fn name(&self) -> &str {
        "dummies"
    }

    fn usage(&self) -> &str {
        "Creates a new dataframe with dummy variables"
    }

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

    fn examples(&self) -> Vec<Example> {
        vec![
            Example {
                description: "Create new dataframe with dummy variables from a dataframe",
                example: "[[a b]; [1 2] [3 4]] | into df | dummies",
                result: Some(
                    NuDataFrame::try_from_columns(vec![
                        Column::new(
                            "a_1".to_string(),
                            vec![Value::test_int(1), Value::test_int(0)],
                        ),
                        Column::new(
                            "a_3".to_string(),
                            vec![Value::test_int(0), Value::test_int(1)],
                        ),
                        Column::new(
                            "b_2".to_string(),
                            vec![Value::test_int(1), Value::test_int(0)],
                        ),
                        Column::new(
                            "b_4".to_string(),
                            vec![Value::test_int(0), Value::test_int(1)],
                        ),
                    ])
                    .expect("simple df for test should not fail")
                    .into_value(Span::test_data()),
                ),
            },
            Example {
                description: "Create new dataframe with dummy variables from a series",
                example: "[1 2 2 3 3] | into df | dummies",
                result: Some(
                    NuDataFrame::try_from_columns(vec![
                        Column::new(
                            "0_1".to_string(),
                            vec![
                                Value::test_int(1),
                                Value::test_int(0),
                                Value::test_int(0),
                                Value::test_int(0),
                                Value::test_int(0),
                            ],
                        ),
                        Column::new(
                            "0_2".to_string(),
                            vec![
                                Value::test_int(0),
                                Value::test_int(1),
                                Value::test_int(1),
                                Value::test_int(0),
                                Value::test_int(0),
                            ],
                        ),
                        Column::new(
                            "0_3".to_string(),
                            vec![
                                Value::test_int(0),
                                Value::test_int(0),
                                Value::test_int(0),
                                Value::test_int(1),
                                Value::test_int(1),
                            ],
                        ),
                    ])
                    .expect("simple df for test should not fail")
                    .into_value(Span::test_data()),
                ),
            },
        ]
    }

    fn run(
        &self,
        engine_state: &EngineState,
        stack: &mut Stack,
        call: &Call,
        input: PipelineData,
    ) -> Result<PipelineData, ShellError> {
        command(engine_state, stack, call, input)
    }
}

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

    df.as_ref()
        .to_dummies()
        .map_err(|e| {
            ShellError::GenericError(
                "Error calculating dummies".into(),
                e.to_string(),
                Some(call.head),
                Some("The only allowed column types for dummies are String or Int".into()),
                Vec::new(),
            )
        })
        .map(|df| PipelineData::Value(NuDataFrame::dataframe_into_value(df, call.head), None))
}

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

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