Added documentation explanation explaining how to select all columns with polars col (#13806)

# Description
Previously there were no examples or explanations that you can use '*'
to select all columns. Updated description and added a new example.
This commit is contained in:
Jack Wright 2024-09-08 10:12:03 -07:00 committed by GitHub
parent 3e074bc447
commit 1e64f59220
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@ -1,7 +1,12 @@
use crate::{dataframe::values::NuExpression, values::CustomValueSupport, PolarsPlugin};
use crate::{
dataframe::values::NuExpression,
values::{Column, CustomValueSupport, NuDataFrame},
PolarsPlugin,
};
use nu_plugin::{EngineInterface, EvaluatedCall, PluginCommand};
use nu_protocol::{
record, Category, Example, LabeledError, PipelineData, Signature, SyntaxShape, Type, Value,
record, Category, Example, LabeledError, PipelineData, Signature, Span, SyntaxShape, Type,
Value,
};
use polars::prelude::col;
@ -24,21 +29,35 @@ impl PluginCommand for ExprCol {
.required(
"column name",
SyntaxShape::String,
"Name of column to be used",
"Name of column to be used. '*' can be used for all columns.",
)
.input_output_type(Type::Any, Type::Custom("expression".into()))
.category(Category::Custom("expression".into()))
}
fn examples(&self) -> Vec<Example> {
vec![Example {
description: "Creates a named column expression and converts it to a nu object",
example: "polars col a | polars into-nu",
result: Some(Value::test_record(record! {
"expr" => Value::test_string("column"),
"value" => Value::test_string("a"),
})),
}]
vec![
Example {
description: "Creates a named column expression and converts it to a nu object",
example: "polars col a | polars into-nu",
result: Some(Value::test_record(record! {
"expr" => Value::test_string("column"),
"value" => Value::test_string("a"),
})),
},
Example {
description: "Select all columns using the asterisk wildcard.",
example: "[[a b]; [x 1] [y 2] [z 3]] | polars into-df | polars select (polars col '*') | polars collect",
result: Some(
NuDataFrame::try_from_columns(vec![
Column::new("a".to_string(), vec![Value::test_string("x"), Value::test_string("y"), Value::test_string("z")]),
Column::new("b".to_string(), vec![Value::test_int(1), Value::test_int(2), Value::test_int(3)]),
],None)
.expect("should not fail")
.into_value(Span::test_data()),
),
},
]
}
fn search_terms(&self) -> Vec<&str> {