nushell/crates/nu-command/src/dataframe/eager/to_df.rs

use super::super::values::{Column, NuDataFrame};

use nu_protocol::{
    ast::Call,
    engine::{Command, EngineState, Stack},
    Category, Example, PipelineData, ShellError, Signature, Span, Type, Value,
};

#[derive(Clone)]
pub struct ToDataFrame;

impl Command for ToDataFrame {
    fn name(&self) -> &str {
        "into df"
    }

    fn usage(&self) -> &str {
        "Converts a list, table or record into a dataframe"
    }

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

    fn examples(&self) -> Vec<Example> {
        vec![
            Example {
                description: "Takes a dictionary and creates a dataframe",
                example: "[[a b];[1 2] [3 4]] | into df",
                result: Some(
                    NuDataFrame::try_from_columns(vec![
                        Column::new(
                            "a".to_string(),
                            vec![Value::test_int(1), Value::test_int(3)],
                        ),
                        Column::new(
                            "b".to_string(),
                            vec![Value::test_int(2), Value::test_int(4)],
                        ),
                    ])
                    .expect("simple df for test should not fail")
                    .into_value(Span::test_data()),
                ),
            },
            Example {
                description: "Takes a list of tables and creates a dataframe",
                example: "[[1 2 a] [3 4 b] [5 6 c]] | into df",
                result: Some(
                    NuDataFrame::try_from_columns(vec![
                        Column::new(
                            "0".to_string(),
                            vec![Value::test_int(1), Value::test_int(3), Value::test_int(5)],
                        ),
                        Column::new(
                            "1".to_string(),
                            vec![Value::test_int(2), Value::test_int(4), Value::test_int(6)],
                        ),
                        Column::new(
                            "2".to_string(),
                            vec![
                                Value::test_string("a"),
                                Value::test_string("b"),
                                Value::test_string("c"),
                            ],
                        ),
                    ])
                    .expect("simple df for test should not fail")
                    .into_value(Span::test_data()),
                ),
            },
            Example {
                description: "Takes a list and creates a dataframe",
                example: "[a b c] | into df",
                result: Some(
                    NuDataFrame::try_from_columns(vec![Column::new(
                        "0".to_string(),
                        vec![
                            Value::test_string("a"),
                            Value::test_string("b"),
                            Value::test_string("c"),
                        ],
                    )])
                    .expect("simple df for test should not fail")
                    .into_value(Span::test_data()),
                ),
            },
            Example {
                description: "Takes a list of booleans and creates a dataframe",
                example: "[true true false] | into df",
                result: Some(
                    NuDataFrame::try_from_columns(vec![Column::new(
                        "0".to_string(),
                        vec![
                            Value::test_bool(true),
                            Value::test_bool(true),
                            Value::test_bool(false),
                        ],
                    )])
                    .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> {
        NuDataFrame::try_from_iter(input.into_iter())
            .map(|df| PipelineData::Value(NuDataFrame::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(ToDataFrame {})])
    }
}