nushell/src/commands/group_by.rs

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use crate::commands::WholeStreamCommand;
use crate::data::TaggedDictBuilder;
use crate::errors::ShellError;
use crate::prelude::*;
pub struct GroupBy;
#[derive(Deserialize)]
pub struct GroupByArgs {
column_name: Tagged<String>,
}
impl WholeStreamCommand for GroupBy {
fn name(&self) -> &str {
"group-by"
}
fn signature(&self) -> Signature {
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Signature::build("group-by").required(
"column_name",
SyntaxShape::String,
"the name of the column to group by",
)
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}
fn usage(&self) -> &str {
"Creates a new table with the data from the table rows grouped by the column given."
}
fn run(
&self,
args: CommandArgs,
registry: &CommandRegistry,
) -> Result<OutputStream, ShellError> {
args.process(registry, group_by)?.run()
}
}
pub fn group_by(
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GroupByArgs { column_name }: GroupByArgs,
RunnableContext { input, name, .. }: RunnableContext,
) -> Result<OutputStream, ShellError> {
let stream = async_stream! {
let values: Vec<Tagged<Value>> = input.values.collect().await;
if values.is_empty() {
yield Err(ShellError::labeled_error(
"Expected table from pipeline",
"requires a table input",
column_name.span()
))
} else {
match group(&column_name, values, name) {
Ok(grouped) => yield ReturnSuccess::value(grouped),
Err(err) => yield Err(err)
}
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}
};
Ok(stream.to_output_stream())
}
pub fn group(
column_name: &Tagged<String>,
values: Vec<Tagged<Value>>,
tag: impl Into<Tag>,
) -> Result<Tagged<Value>, ShellError> {
let tag = tag.into();
let mut groups = indexmap::IndexMap::new();
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for value in values {
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let group_key = value.get_data_by_key(column_name.borrow_spanned());
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if group_key.is_none() {
let possibilities = value.data_descriptors();
let mut possible_matches: Vec<_> = possibilities
.iter()
.map(|x| (natural::distance::levenshtein_distance(x, column_name), x))
.collect();
possible_matches.sort();
if possible_matches.len() > 0 {
return Err(ShellError::labeled_error(
"Unknown column",
format!("did you mean '{}'?", possible_matches[0].1),
column_name.tag(),
));
} else {
return Err(ShellError::labeled_error(
"Unknown column",
"row does not contain this column",
column_name.tag(),
));
}
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}
let group_key = group_key.unwrap().as_string()?;
let group = groups.entry(group_key).or_insert(vec![]);
group.push(value);
}
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let mut out = TaggedDictBuilder::new(&tag);
for (k, v) in groups.iter() {
out.insert(k, Value::table(v));
}
Ok(out.into_tagged_value())
}
#[cfg(test)]
mod tests {
use crate::commands::group_by::group;
use crate::data::meta::*;
use crate::Value;
use indexmap::IndexMap;
fn string(input: impl Into<String>) -> Tagged<Value> {
Value::string(input.into()).tagged_unknown()
}
fn row(entries: IndexMap<String, Tagged<Value>>) -> Tagged<Value> {
Value::row(entries).tagged_unknown()
}
fn table(list: &Vec<Tagged<Value>>) -> Tagged<Value> {
Value::table(list).tagged_unknown()
}
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fn nu_releases_commiters() -> Vec<Tagged<Value>> {
vec![
row(
indexmap! {"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("August 23-2019")},
),
row(
indexmap! {"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("August 23-2019")},
),
row(
indexmap! {"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("October 10-2019")},
),
row(
indexmap! {"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("Sept 24-2019")},
),
row(
indexmap! {"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("October 10-2019")},
),
row(
indexmap! {"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("Sept 24-2019")},
),
row(
indexmap! {"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("October 10-2019")},
),
row(
indexmap! {"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("Sept 24-2019")},
),
row(
indexmap! {"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("August 23-2019")},
),
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]
}
#[test]
fn groups_table_by_date_column() {
let for_key = String::from("date").tagged_unknown();
assert_eq!(
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group(&for_key, nu_releases_commiters(), Tag::unknown()).unwrap(),
row(indexmap! {
"August 23-2019".into() => table(&vec![
row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("August 23-2019")}),
row(indexmap!{"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("August 23-2019")}),
row(indexmap!{"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("August 23-2019")})
]),
"October 10-2019".into() => table(&vec![
row(indexmap!{"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("October 10-2019")}),
row(indexmap!{"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("October 10-2019")}),
row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("October 10-2019")})
]),
"Sept 24-2019".into() => table(&vec![
row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("Sept 24-2019")}),
row(indexmap!{"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("Sept 24-2019")}),
row(indexmap!{"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("Sept 24-2019")})
]),
})
);
}
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#[test]
fn groups_table_by_country_column() {
let for_key = String::from("country").tagged_unknown();
assert_eq!(
group(&for_key, nu_releases_commiters(), Tag::unknown()).unwrap(),
row(indexmap! {
"EC".into() => table(&vec![
row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("August 23-2019")}),
row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("Sept 24-2019")}),
row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("October 10-2019")})
]),
"NZ".into() => table(&vec![
row(indexmap!{"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("August 23-2019")}),
row(indexmap!{"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("October 10-2019")}),
row(indexmap!{"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("Sept 24-2019")})
]),
"US".into() => table(&vec![
row(indexmap!{"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("October 10-2019")}),
row(indexmap!{"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("Sept 24-2019")}),
row(indexmap!{"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("August 23-2019")}),
]),
})
);
}
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}