use crate::values::NuDataFrame;
use crate::{
PolarsPlugin,
dataframe::values::NuSelector,
values::{CustomValueSupport, PolarsPluginType},
};
use log::debug;
use nu_plugin::{EngineInterface, EvaluatedCall, PluginCommand};
use nu_protocol::{Category, Example, LabeledError, PipelineData, Signature, Span, Type};
use polars::df;
use polars::prelude::Selector;
#[derive(Clone)]
pub struct SelectorAlpha;
impl PluginCommand for SelectorAlpha {
type Plugin = PolarsPlugin;
fn name(&self) -> &str {
"polars selector alpha"
}
fn description(&self) -> &str {
r#"Select all columns with alphabetic names (eg: only letters). Matching column names cannot contain *any* non-alphabetic characters. Note that the definition of "alphabetic" consists of all valid Unicode alphabetic characters by default; this can be changed by setting `--ascii-only`."#
}
fn signature(&self) -> Signature {
Signature::build(self.name())
.switch("ascii-only", "Indicate whether to consider only ASCII alphabetic characters, or the full Unicode range of valid letters (accented, idiographic, etc).", Some('a'))
.switch("ignore-spaces", "Indicate whether to ignore the presence of spaces in column names; if so, only the other (non-space) characters are considered. ", Some('s'))
.input_output_type(Type::Any, PolarsPluginType::NuSelector.into())
.category(Category::Custom("expression".into()))
}
fn examples(&self) -> Vec<Example<'_>> {
vec![
Example {
example: r#"
{
"no1": [100, 200, 300],
"café": ["espresso", "latte", "mocha"],
"t or f": [true, false, null],
"hmm": ["aaa", "bbb", "ccc"],
"都市": ["東京", "大阪", "京都"],
} |
polars into-df --as-columns |
polars select (polars selector alpha) |
polars sort-by café hmm 都市 |
polars collect
"#,
description: "Select columns with alphabetic names; note that accented characters and kanji are recognised as alphabetic here.",
result: Some(
NuDataFrame::from(
df!(
"café" => ["espresso", "latte", "mocha"],
"hmm" => ["aaa", "bbb", "ccc"],
"都市" => ["東京", "大阪", "京都"],
)
.expect("Failed to create expected DataFrame"),
)
.into_value(Span::test_data()),
),
},
Example {
example: r#"
{
"no1": [100, 200, 300],
"café": ["espresso", "latte", "mocha"],
"t or f": [true, false, null],
"hmm": ["aaa", "bbb", "ccc"],
"都市": ["東京", "大阪", "京都"],
} |
polars into-df --as-columns |
polars select (polars selector alpha --ascii-only) |
polars collect
"#,
description: r#"Constrain the definition of "alphabetic" to ASCII characters only."#,
result: Some(
NuDataFrame::from(
df!(
"hmm" => ["aaa", "bbb", "ccc"],
)
.expect("Failed to create expected DataFrame"),
)
.into_value(Span::test_data()),
),
},
Example {
example: r#"
{
"no1": [100, 200, 300],
"café": ["espresso", "latte", "mocha"],
"t or f": [true, false, null],
"hmm": ["aaa", "bbb", "ccc"],
"都市": ["東京", "大阪", "京都"],
} |
polars into-df --as-columns |
polars select (polars selector alpha --ascii-only --ignore-spaces) |
polars sort-by "t or f" hmm |
polars collect
"#,
description: r#"Constrain the definition of "alphabetic" to ASCII characters only and ignore whitespace."#,
result: Some(
NuDataFrame::from(
df!(
"t or f" => [None, Some(false), Some(true)],
"hmm" => ["ccc", "bbb", "aaa"],
)
.expect("Failed to create expected DataFrame"),
)
.into_value(Span::test_data()),
),
},
Example {
example: r#"
{
"no1": [100, 200, 300],
"café": ["espresso", "latte", "mocha"],
"t or f": [true, false, null],
"hmm": ["aaa", "bbb", "ccc"],
"都市": ["東京", "大阪", "京都"],
} |
polars into-df --as-columns |
polars select (polars selector alpha | polars selector not) |
polars sort-by no1 "t or f"|
polars collect
"#,
description: r#"Select all columns *except* for those with alphabetic names."#,
result: Some(
NuDataFrame::from(
df!(
"no1" => [100, 200, 300],
"t or f" => [Some(true), Some(false), None],
)
.expect("Failed to create expected DataFrame"),
)
.into_value(Span::test_data()),
),
},
Example {
example: r#"
{
"no1": [100, 200, 300],
"café": ["espresso", "latte", "mocha"],
"t or f": [true, false, null],
"hmm": ["aaa", "bbb", "ccc"],
"都市": ["東京", "大阪", "京都"],
} |
polars into-df --as-columns |
polars select (polars selector alpha --ignore-spaces | polars selector not) |
polars sort-by no1 |
polars collect
"#,
description: r#"Select all columns *except* for those with alphabetic names and do not have spaces."#,
result: Some(
NuDataFrame::from(
df!(
"no1" => [100, 200, 300],
)
.expect("Failed to create expected DataFrame"),
)
.into_value(Span::test_data()),
),
},
]
}
fn search_terms(&self) -> Vec<&str> {
vec!["columns", "select", "alpha"]
}
fn run(
&self,
plugin: &Self::Plugin,
engine: &EngineInterface,
call: &EvaluatedCall,
mut input: PipelineData,
) -> Result<PipelineData, LabeledError> {
let metadata = input.take_metadata();
let ascii_only = call.has_flag("ascii-only")?;
let ignore_spaces = call.has_flag("ignore-spaces")?;
let re_alpha = if ascii_only {
"a-zA-Z"
} else {
r"\p{Alphabetic}"
};
let re_space = if ignore_spaces { " " } else { "" };
let pattern = format!("^[{re_alpha}{re_space}]+$");
debug!("SelectorAlpha: pattern = {pattern}");
let selector = Selector::Matches(pattern.into());
let nu_selector = NuSelector::from(selector);
nu_selector
.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<(), nu_protocol::ShellError> {
test_polars_plugin_command(&SelectorAlpha)
}
}