nushell/crates/nu-command/src/commands/dataframe/drop_duplicates.rs
Fernando Herrera f1ee9113ac
All is a DataFrame (#3812)
* nuframe in its own type in UntaggedValue

* Removed eager dataframe from enum

* Dataframe created from list of values

* Corrected order in dataframe columns

* Returned tag from stream collection

* Removed series from dataframe commands

* Arithmetic operators

* forced push

* forced push

* Replace all command

* String commands

* appending operations with dfs

* Testing suite for dataframes

* Unit test for dataframe commands

* improved equality for dataframes
2021-07-25 22:01:54 +12:00

96 lines
2.8 KiB
Rust

use crate::prelude::*;
use nu_engine::WholeStreamCommand;
use nu_errors::ShellError;
use nu_protocol::{
dataframe::{Column, NuDataFrame},
Signature, SyntaxShape, UntaggedValue, Value,
};
use super::utils::{convert_columns, parse_polars_error};
pub struct DataFrame;
impl WholeStreamCommand for DataFrame {
fn name(&self) -> &str {
"dataframe drop-duplicates"
}
fn usage(&self) -> &str {
"[DataFrame] Drops duplicate values in dataframe"
}
fn signature(&self) -> Signature {
Signature::build("dataframe drop-duplicates")
.optional(
"subset",
SyntaxShape::Table,
"subset of columns to drop duplicates",
)
.switch("maintain", "maintain order", Some('m'))
}
fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
command(args)
}
fn examples(&self) -> Vec<Example> {
vec![Example {
description: "drop duplicates",
example: "[[a b]; [1 2] [3 4] [1 2]] | dataframe to-df | dataframe drop-duplicates",
result: Some(vec![NuDataFrame::try_from_columns(
vec![
Column::new(
"a".to_string(),
vec![UntaggedValue::int(1).into(), UntaggedValue::int(3).into()],
),
Column::new(
"b".to_string(),
vec![UntaggedValue::int(2).into(), UntaggedValue::int(4).into()],
),
],
&Span::default(),
)
.expect("simple df for test should not fail")
.into_value(Tag::default())]),
}]
}
}
fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
let tag = args.call_info.name_tag.clone();
// Extracting the selection columns of the columns to perform the aggregation
let columns: Option<Vec<Value>> = args.opt(0)?;
let (subset, col_span) = match columns {
Some(cols) => {
let (agg_string, col_span) = convert_columns(&cols, &tag)?;
(Some(agg_string), col_span)
}
None => (None, Span::unknown()),
};
let (df, _) = NuDataFrame::try_from_stream(&mut args.input, &tag.span)?;
let subset_slice = subset.as_ref().map(|cols| &cols[..]);
let res = df
.as_ref()
.drop_duplicates(args.has_flag("maintain"), subset_slice)
.map_err(|e| parse_polars_error::<&str>(&e, &col_span, None))?;
Ok(OutputStream::one(NuDataFrame::dataframe_to_value(res, tag)))
}
#[cfg(test)]
mod tests {
use super::DataFrame;
use super::ShellError;
#[test]
fn examples_work_as_expected() -> Result<(), ShellError> {
use crate::examples::test_dataframe as test_examples;
test_examples(DataFrame {})
}
}