nushell/crates/nu-cmd-dataframe/src/dataframe/series/string/str_slice.rs
Eric Hodel a95a4505ef
Convert Shellerror::GenericError to named fields (#11230)
# Description

Replace `.to_string()` used in `GenericError` with `.into()` as
`.into()` seems more popular

Replace `Vec::new()` used in `GenericError` with `vec![]` as `vec![]`
seems more popular

(There are so, so many)
2023-12-07 00:40:03 +01:00

103 lines
3.0 KiB
Rust

use super::super::super::values::{Column, NuDataFrame};
use nu_engine::CallExt;
use nu_protocol::{
ast::Call,
engine::{Command, EngineState, Stack},
Category, Example, PipelineData, ShellError, Signature, Span, SyntaxShape, Type, Value,
};
use polars::prelude::{IntoSeries, Utf8NameSpaceImpl};
#[derive(Clone)]
pub struct StrSlice;
impl Command for StrSlice {
fn name(&self) -> &str {
"dfr str-slice"
}
fn usage(&self) -> &str {
"Slices the string from the start position until the selected length."
}
fn signature(&self) -> Signature {
Signature::build(self.name())
.required("start", SyntaxShape::Int, "start of slice")
.named("length", SyntaxShape::Int, "optional length", Some('l'))
.input_output_type(
Type::Custom("dataframe".into()),
Type::Custom("dataframe".into()),
)
.category(Category::Custom("dataframe".into()))
}
fn examples(&self) -> Vec<Example> {
vec![Example {
description: "Creates slices from the strings",
example: "[abcded abc321 abc123] | dfr into-df | dfr str-slice 1 --length 2",
result: Some(
NuDataFrame::try_from_columns(vec![Column::new(
"0".to_string(),
vec![
Value::test_string("bc"),
Value::test_string("bc"),
Value::test_string("bc"),
],
)])
.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 start: i64 = call.req(engine_state, stack, 0)?;
let length: Option<i64> = call.get_flag(engine_state, stack, "length")?;
let length = length.map(|v| v as u64);
let df = NuDataFrame::try_from_pipeline(input, call.head)?;
let series = df.as_series(call.head)?;
let chunked = series.utf8().map_err(|e| ShellError::GenericError {
error: "Error casting to string".into(),
msg: e.to_string(),
span: Some(call.head),
help: Some("The str-slice command can only be used with string columns".into()),
inner: vec![],
})?;
let mut res = chunked.str_slice(start, length);
res.rename(series.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::super::test_dataframe::test_dataframe;
use super::*;
#[test]
fn test_examples() {
test_dataframe(vec![Box::new(StrSlice {})])
}
}