use crate::dataframe::values::{Column, NuDataFrame, NuSchema};
use nu_engine::command_prelude::*;
use polars::prelude::*;
#[derive(Clone)]
pub struct ToDataFrame;
impl Command for ToDataFrame {
fn name(&self) -> &str {
"dfr into-df"
}
fn usage(&self) -> &str {
"Converts a list, table or record into a dataframe."
}
fn signature(&self) -> Signature {
Signature::build(self.name())
.named(
"schema",
SyntaxShape::Record(vec![]),
r#"Polars Schema in format [{name: str}]. CSV, JSON, and JSONL files"#,
Some('s'),
)
.input_output_type(Type::Any, 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]] | dfr 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)],
),
],
None,
)
.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]] | dfr 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"),
],
),
],
None,
)
.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] | dfr 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"),
],
)],
None,
)
.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] | dfr 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),
],
)],
None,
)
.expect("simple df for test should not fail")
.into_value(Span::test_data()),
),
},
Example {
description: "Convert to a dataframe and provide a schema",
example: "{a: 1, b: {a: [1 2 3]}, c: [a b c]}| dfr into-df -s {a: u8, b: {a: list<u64>}, c: list<str>}",
result: Some(
NuDataFrame::try_from_series(vec![
Series::new("a", &[1u8]),
{
let dtype = DataType::Struct(vec![Field::new("a", DataType::List(Box::new(DataType::UInt64)))]);
let vals = vec![AnyValue::StructOwned(
Box::new((vec![AnyValue::List(Series::new("a", &[1u64, 2, 3]))], vec![Field::new("a", DataType::String)]))); 1];
Series::from_any_values_and_dtype("b", &vals, &dtype, false)
.expect("Struct series should not fail")
},
{
let dtype = DataType::List(Box::new(DataType::String));
let vals = vec![AnyValue::List(Series::new("c", &["a", "b", "c"]))];
Series::from_any_values_and_dtype("c", &vals, &dtype, false)
.expect("List series should not fail")
}
], Span::test_data())
.expect("simple df for test should not fail")
.into_value(Span::test_data()),
),
},
Example {
description: "Convert to a dataframe and provide a schema that adds a new column",
example: r#"[[a b]; [1 "foo"] [2 "bar"]] | dfr into-df -s {a: u8, b:str, c:i64} | dfr fill-null 3"#,
result: Some(NuDataFrame::try_from_series(vec![
Series::new("a", [1u8, 2]),
Series::new("b", ["foo", "bar"]),
Series::new("c", [3i64, 3]),
], Span::test_data())
.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> {
let maybe_schema = call
.get_flag(engine_state, stack, "schema")?
.map(|schema| NuSchema::try_from(&schema))
.transpose()?;
let df = NuDataFrame::try_from_iter(input.into_iter(), maybe_schema.clone())?;
Ok(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 {})])
}
}