use crate::values::{NuExpression, PolarsPluginType};
use std::sync::Arc;
use crate::{
PolarsPlugin,
dataframe::values::{Column, NuDataFrame, NuSchema},
values::CustomValueSupport,
};
use chrono::{DateTime, FixedOffset};
use nu_plugin::{EngineInterface, EvaluatedCall, PluginCommand};
use nu_protocol::{
Category, Example, LabeledError, PipelineData, ShellError, Signature, Span, Spanned,
SyntaxShape, Value,
};
use polars::{
datatypes::{DataType, TimeUnit},
prelude::{Field, NamedFrom, Schema},
series::Series,
};
#[derive(Clone)]
pub struct ExprDatePart;
impl PluginCommand for ExprDatePart {
type Plugin = PolarsPlugin;
fn name(&self) -> &str {
"polars datepart"
}
fn description(&self) -> &str {
"Creates an expression for capturing the specified datepart in a column."
}
fn signature(&self) -> Signature {
Signature::build(self.name())
.required(
"Datepart name",
SyntaxShape::String,
"Part of the date to capture. Possible values are year, quarter, month, week, weekday, day, hour, minute, second, millisecond, microsecond, nanosecond.",
)
.input_output_type(
PolarsPluginType::NuExpression.into(),
PolarsPluginType::NuExpression.into(),
)
.category(Category::Custom("expression".into()))
}
fn examples(&self) -> Vec<Example<'_>> {
let dt = DateTime::<FixedOffset>::parse_from_str(
"2021-12-30T01:02:03.123456789 +0000",
"%Y-%m-%dT%H:%M:%S.%9f %z",
)
.expect("date calculation should not fail in test");
vec![
Example {
description: "Creates an expression to capture the year date part",
example: r#"[["2021-12-30T01:02:03.123456789"]] | polars into-df | polars as-datetime "%Y-%m-%dT%H:%M:%S.%9f" --naive | polars with-column [(polars col datetime | polars datepart year | polars as datetime_year )]"#,
result: Some(
NuDataFrame::try_from_columns(
vec![
Column::new("datetime".to_string(), vec![Value::test_date(dt)]),
Column::new("datetime_year".to_string(), vec![Value::test_int(2021)]),
],
Some(NuSchema::new(Arc::new(Schema::from_iter(vec![
Field::new(
"datetime".into(),
DataType::Datetime(TimeUnit::Nanoseconds, None),
),
Field::new("datetime_year".into(), DataType::Int64),
])))),
Span::test_data(),
)
.expect("simple df for test should not fail")
.into_value(Span::test_data()),
),
},
Example {
description: "Creates an expression to capture multiple date parts",
example: r#"[["2021-12-30T01:02:03.123456789"]] | polars into-df | polars as-datetime "%Y-%m-%dT%H:%M:%S.%9f" --naive |
polars with-column [ (polars col datetime | polars datepart year | polars as datetime_year ),
(polars col datetime | polars datepart month | polars as datetime_month ),
(polars col datetime | polars datepart day | polars as datetime_day ),
(polars col datetime | polars datepart hour | polars as datetime_hour ),
(polars col datetime | polars datepart minute | polars as datetime_minute ),
(polars col datetime | polars datepart second | polars as datetime_second ),
(polars col datetime | polars datepart nanosecond | polars as datetime_ns ) ]"#,
result: Some(
NuDataFrame::try_from_series_vec(
vec![
Series::new("datetime".into(), &[dt.timestamp_nanos_opt()])
.cast(&DataType::Datetime(TimeUnit::Nanoseconds, None))
.expect("Error casting to datetime type"),
Series::new("datetime_year".into(), &[2021_i64]), Series::new("datetime_month".into(), &[12_i8]),
Series::new("datetime_day".into(), &[30_i8]),
Series::new("datetime_hour".into(), &[1_i8]),
Series::new("datetime_minute".into(), &[2_i8]),
Series::new("datetime_second".into(), &[3_i8]),
Series::new("datetime_ns".into(), &[123456789_i64]), ],
Span::test_data(),
)
.expect("simple df for test should not fail")
.into_value(Span::test_data()),
),
},
]
}
fn search_terms(&self) -> Vec<&str> {
vec![
"year",
"month",
"week",
"weekday",
"quarter",
"day",
"hour",
"minute",
"second",
"millisecond",
"microsecond",
"nanosecond",
]
}
fn run(
&self,
plugin: &Self::Plugin,
engine: &EngineInterface,
call: &EvaluatedCall,
mut input: PipelineData,
) -> Result<PipelineData, LabeledError> {
let part: Spanned<String> = call.req(0)?;
let metadata = input.take_metadata();
let expr = NuExpression::try_from_pipeline(plugin, input, call.head)?;
let expr_dt = expr.into_polars().dt();
let expr: NuExpression = match part.item.as_str() {
"year" => expr_dt.year(),
"quarter" => expr_dt.quarter(),
"month" => expr_dt.month(),
"week" => expr_dt.week(),
"day" => expr_dt.day(),
"hour" => expr_dt.hour(),
"minute" => expr_dt.minute(),
"second" => expr_dt.second(),
"millisecond" => expr_dt.millisecond(),
"microsecond" => expr_dt.microsecond(),
"nanosecond" => expr_dt.nanosecond(),
_ => {
return Err(LabeledError::from(ShellError::UnsupportedInput {
msg: format!("{} is not a valid datepart, expected one of year, month, day, hour, minute, second, millisecond, microsecond, nanosecond", part.item),
input: "value originates from here".to_string(),
msg_span: call.head,
input_span: part.span,
}))
}
}.into();
expr.to_pipeline_data(plugin, engine, call.head)
.map_err(LabeledError::from)
.map(|pd| pd.set_metadata(metadata))
}
}
#[cfg(test)]
mod test {
use super::*;
use crate::test::test_polars_plugin_command;
#[test]
fn test_examples() -> Result<(), ShellError> {
test_polars_plugin_command(&ExprDatePart)
}
}