nushell/crates/nu-command/src/dataframe/series/cumulative.rs
2022-04-19 00:34:10 +12:00

139 lines
3.9 KiB
Rust

use super::super::values::{Column, NuDataFrame};
use nu_engine::CallExt;
use nu_protocol::{
ast::Call,
engine::{Command, EngineState, Stack},
Category, Example, PipelineData, ShellError, Signature, Span, Spanned, SyntaxShape, Value,
};
use polars::prelude::{DataType, IntoSeries};
enum CumType {
Min,
Max,
Sum,
}
impl CumType {
fn from_str(roll_type: &str, span: Span) -> Result<Self, ShellError> {
match roll_type {
"min" => Ok(Self::Min),
"max" => Ok(Self::Max),
"sum" => Ok(Self::Sum),
_ => Err(ShellError::GenericError(
"Wrong operation".into(),
"Operation not valid for cumulative".into(),
Some(span),
Some("Allowed values: max, min, sum".into()),
Vec::new(),
)),
}
}
fn to_str(&self) -> &'static str {
match self {
CumType::Min => "cumulative_min",
CumType::Max => "cumulative_max",
CumType::Sum => "cumulative_sum",
}
}
}
#[derive(Clone)]
pub struct Cumulative;
impl Command for Cumulative {
fn name(&self) -> &str {
"dfr cumulative"
}
fn usage(&self) -> &str {
"Cumulative calculation for a series"
}
fn signature(&self) -> Signature {
Signature::build(self.name())
.required("type", SyntaxShape::String, "rolling operation")
.switch("reverse", "Reverse cumulative calculation", Some('r'))
.category(Category::Custom("dataframe".into()))
}
fn examples(&self) -> Vec<Example> {
vec![Example {
description: "Cumulative sum for a series",
example: "[1 2 3 4 5] | dfr to-df | dfr cumulative sum",
result: Some(
NuDataFrame::try_from_columns(vec![Column::new(
"0_cumulative_sum".to_string(),
vec![
Value::test_int(1),
Value::test_int(3),
Value::test_int(6),
Value::test_int(10),
Value::test_int(15),
],
)])
.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 cum_type: Spanned<String> = call.req(engine_state, stack, 0)?;
let reverse = call.has_flag("reverse");
let df = NuDataFrame::try_from_pipeline(input, call.head)?;
let series = df.as_series(call.head)?;
if let DataType::Object(_) = series.dtype() {
return Err(ShellError::GenericError(
"Found object series".into(),
"Series of type object cannot be used for cumulative operation".into(),
Some(call.head),
None,
Vec::new(),
));
}
let cum_type = CumType::from_str(&cum_type.item, cum_type.span)?;
let mut res = match cum_type {
CumType::Max => series.cummax(reverse),
CumType::Min => series.cummin(reverse),
CumType::Sum => series.cumsum(reverse),
};
let name = format!("{}_{}", series.name(), cum_type.to_str());
res.rename(&name);
NuDataFrame::try_from_series(vec![res.into_series()], call.head)
.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(Cumulative {})])
}
}