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Move 'nth' into 'select' (#4385)

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JT 2022-02-09 09:59:40 -05:00 committed by GitHub
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18 changed files with 190 additions and 259 deletions
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8
crates/nu-command/src/core_commands/tutor.rs
View File

@ -176,10 +176,10 @@ using Nushell commands.
To get the 3rd row in the table, you can use the `nth` command:
```
ls | nth 2
ls | select 2
```
This will get the 3rd (note that `nth` is zero-based) row in the table created
by the `ls` command. You can use `nth` on any table created by other commands
This will get the 3rd (note that `select` is zero-based) row in the table created
by the `ls` command. You can use `select` on any table created by other commands
as well.
You can also access the column of data in one of two ways. If you want
@ -218,7 +218,7 @@ like lists and tables.
To reach a cell of data from a table, you can combine a row operation and a
column operation.
```
ls | nth 4 | get name
ls | select 4 | get name
```
You can combine these operations into one step using a shortcut.
```

1
crates/nu-command/src/default_context.rs
View File

@ -84,7 +84,6 @@ pub fn create_default_context(cwd: impl AsRef<Path>) -> EngineState {
Last,
Length,
Lines,
Nth,
ParEach,
ParEachGroup,
Prepend,

2
crates/nu-command/src/filters/columns.rs
View File

@ -35,7 +35,7 @@ impl Command for Columns {
result: None,
},
Example {
example: "[[name,age,grade]; [bill,20,a]] | columns | nth 1",
example: "[[name,age,grade]; [bill,20,a]] | columns | select 1",
description: "Get the second column from the table",
result: None,
},

2
crates/nu-command/src/filters/mod.rs
View File

@ -22,7 +22,6 @@ mod length;
mod lines;
mod merge;
mod move_;
mod nth;
mod par_each;
mod par_each_group;
mod prepend;
@ -69,7 +68,6 @@ pub use length::Length;
pub use lines::Lines;
pub use merge::Merge;
pub use move_::Move;
pub use nth::Nth;
pub use par_each::ParEach;
pub use par_each_group::ParEachGroup;
pub use prepend::Prepend;

152
crates/nu-command/src/filters/nth.rs
View File

@ -1,152 +0,0 @@
use nu_engine::CallExt;
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
Category, Example, IntoInterruptiblePipelineData, PipelineData, PipelineIterator, ShellError,
Signature, Span, SyntaxShape, Value,
};
#[derive(Clone)]
pub struct Nth;
impl Command for Nth {
fn name(&self) -> &str {
"nth"
}
fn signature(&self) -> Signature {
Signature::build("nth")
.rest("rest", SyntaxShape::Int, "the number of the row to return")
.switch("skip", "Skip the rows instead of selecting them", Some('s'))
.category(Category::Filters)
}
fn usage(&self) -> &str {
"Return or skip only the selected rows."
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
example: "[sam,sarah,2,3,4,5] | nth 0 1 2",
description: "Get the first, second, and third row",
result: Some(Value::List {
vals: vec![
Value::test_string("sam"),
Value::test_string("sarah"),
Value::test_int(2),
],
span: Span::test_data(),
}),
},
Example {
example: "[0,1,2,3,4,5] | nth 0 1 2",
description: "Get the first, second, and third row",
result: Some(Value::List {
vals: vec![Value::test_int(0), Value::test_int(1), Value::test_int(2)],
span: Span::test_data(),
}),
},
Example {
example: "[0,1,2,3,4,5] | nth -s 0 1 2",
description: "Skip the first, second, and third row",
result: Some(Value::List {
vals: vec![Value::test_int(3), Value::test_int(4), Value::test_int(5)],
span: Span::test_data(),
}),
},
Example {
example: "[0,1,2,3,4,5] | nth 0 2 4",
description: "Get the first, third, and fifth row",
result: Some(Value::List {
vals: vec![Value::test_int(0), Value::test_int(2), Value::test_int(4)],
span: Span::test_data(),
}),
},
Example {
example: "[0,1,2,3,4,5] | nth 2 0 4",
description: "Get the first, third, and fifth row",
result: Some(Value::List {
vals: vec![Value::test_int(0), Value::test_int(2), Value::test_int(4)],
span: Span::test_data(),
}),
},
]
}
fn run(
&self,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
let mut rows: Vec<usize> = call.rest(engine_state, stack, 0)?;
rows.sort_unstable();
let skip = call.has_flag("skip");
let pipeline_iter: PipelineIterator = input.into_iter();
Ok(NthIterator {
input: pipeline_iter,
rows,
skip,
current: 0,
}
.into_pipeline_data(engine_state.ctrlc.clone()))
}
}
struct NthIterator {
input: PipelineIterator,
rows: Vec<usize>,
skip: bool,
current: usize,
}
impl Iterator for NthIterator {
type Item = Value;
fn next(&mut self) -> Option<Self::Item> {
loop {
if !self.skip {
if let Some(row) = self.rows.get(0) {
if self.current == *row {
self.rows.remove(0);
self.current += 1;
return self.input.next();
} else {
self.current += 1;
let _ = self.input.next();
continue;
}
} else {
return None;
}
} else if let Some(row) = self.rows.get(0) {
if self.current == *row {
self.rows.remove(0);
self.current += 1;
let _ = self.input.next();
continue;
} else {
self.current += 1;
return self.input.next();
}
} else {
return self.input.next();
}
}
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(Nth {})
}
}

164
crates/nu-command/src/filters/select.rs
View File

@ -1,9 +1,9 @@
use nu_engine::CallExt;
use nu_protocol::ast::{Call, CellPath};
use nu_protocol::ast::{Call, CellPath, PathMember};
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData, ShellError,
Signature, Span, SyntaxShape, Value,
Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData,
PipelineIterator, ShellError, Signature, Span, SyntaxShape, Value,
};
#[derive(Clone)]
@ -14,6 +14,7 @@ impl Command for Select {
"select"
}
// FIXME: also add support for --skip
fn signature(&self) -> Signature {
Signature::build("select")
.rest(
@ -63,9 +64,44 @@ fn select(
columns: Vec<CellPath>,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
if columns.is_empty() {
return Err(ShellError::CantFindColumn(span, span)); //FIXME?
let mut rows = vec![];
let mut new_columns = vec![];
for column in columns {
let CellPath { ref members } = column;
match members.get(0) {
Some(PathMember::Int { val, span }) => {
if members.len() > 1 {
return Err(ShellError::SpannedLabeledError(
"Select only allows row numbers for rows".into(),
"extra after row number".into(),
*span,
));
}
rows.push(*val);
}
_ => new_columns.push(column),
};
}
let columns = new_columns;
let input = if !rows.is_empty() {
rows.sort_unstable();
// let skip = call.has_flag("skip");
let pipeline_iter: PipelineIterator = input.into_iter();
NthIterator {
input: pipeline_iter,
rows,
skip: false,
current: 0,
}
.into_pipeline_data(engine_state.ctrlc.clone())
} else {
input
};
match input {
PipelineData::Value(
@ -78,17 +114,21 @@ fn select(
let mut output = vec![];
for input_val in input_vals {
let mut cols = vec![];
let mut vals = vec![];
for path in &columns {
//FIXME: improve implementation to not clone
let fetcher = input_val.clone().follow_cell_path(&path.members)?;
if !columns.is_empty() {
let mut cols = vec![];
let mut vals = vec![];
for path in &columns {
//FIXME: improve implementation to not clone
let fetcher = input_val.clone().follow_cell_path(&path.members)?;
cols.push(path.into_string());
vals.push(fetcher);
cols.push(path.into_string());
vals.push(fetcher);
}
output.push(Value::Record { cols, vals, span })
} else {
output.push(input_val)
}
output.push(Value::Record { cols, vals, span })
}
Ok(output
@ -97,39 +137,89 @@ fn select(
}
PipelineData::ListStream(stream, ..) => Ok(stream
.map(move |x| {
let mut cols = vec![];
let mut vals = vec![];
for path in &columns {
//FIXME: improve implementation to not clone
match x.clone().follow_cell_path(&path.members) {
Ok(value) => {
cols.push(path.into_string());
vals.push(value);
}
Err(error) => {
cols.push(path.into_string());
vals.push(Value::Error { error });
if !columns.is_empty() {
let mut cols = vec![];
let mut vals = vec![];
for path in &columns {
//FIXME: improve implementation to not clone
match x.clone().follow_cell_path(&path.members) {
Ok(value) => {
cols.push(path.into_string());
vals.push(value);
}
Err(error) => {
cols.push(path.into_string());
vals.push(Value::Error { error });
}
}
}
Value::Record { cols, vals, span }
} else {
x
}
Value::Record { cols, vals, span }
})
.into_pipeline_data(engine_state.ctrlc.clone())),
PipelineData::Value(v, ..) => {
let mut cols = vec![];
let mut vals = vec![];
if !columns.is_empty() {
let mut cols = vec![];
let mut vals = vec![];
for cell_path in columns {
// FIXME: remove clone
let result = v.clone().follow_cell_path(&cell_path.members)?;
for cell_path in columns {
// FIXME: remove clone
let result = v.clone().follow_cell_path(&cell_path.members)?;
cols.push(cell_path.into_string());
vals.push(result);
cols.push(cell_path.into_string());
vals.push(result);
}
Ok(Value::Record { cols, vals, span }.into_pipeline_data())
} else {
Ok(v.into_pipeline_data())
}
Ok(Value::Record { cols, vals, span }.into_pipeline_data())
}
_ => Ok(PipelineData::new(span)),
}
}
struct NthIterator {
input: PipelineIterator,
rows: Vec<usize>,
skip: bool,
current: usize,
}
impl Iterator for NthIterator {
type Item = Value;
fn next(&mut self) -> Option<Self::Item> {
loop {
if !self.skip {
if let Some(row) = self.rows.get(0) {
if self.current == *row {
self.rows.remove(0);
self.current += 1;
return self.input.next();
} else {
self.current += 1;
let _ = self.input.next();
continue;
}
} else {
return None;
}
} else if let Some(row) = self.rows.get(0) {
if self.current == *row {
self.rows.remove(0);
self.current += 1;
let _ = self.input.next();
continue;
} else {
self.current += 1;
return self.input.next();
}
} else {
return self.input.next();
}
}
}
}

4
crates/nu-command/tests/commands/get.rs
View File

@ -108,7 +108,7 @@ fn fetches_more_than_one_column_path() {
arepas = 1
[[fortune_tellers]]
name = "Jonathan Turner"
name = "JT"
arepas = 1
[[fortune_tellers]]
@ -126,7 +126,7 @@ fn fetches_more_than_one_column_path() {
"#
));
assert_eq!(actual.out, "Jonathan Turner");
assert_eq!(actual.out, "JT");
})
}

1
crates/nu-command/tests/commands/mod.rs
View File

@ -34,7 +34,6 @@ mod math;
mod merge;
mod mkdir;
mod move_;
mod nth;
mod open;
mod parse;
mod path;

2
crates/nu-command/tests/commands/move_/column.rs
View File

@ -133,7 +133,7 @@ fn moves_columns_after() {
open sample.csv
| move letters and_more --after column1
| get
| nth 1 2
| select 1 2
| str collect
"#
));

41
crates/nu-command/tests/commands/nth.rs
View File

@ -1,41 +0,0 @@
use nu_test_support::fs::Stub::EmptyFile;
use nu_test_support::playground::Playground;
use nu_test_support::{nu, pipeline};
#[test]
fn selects_a_row() {
Playground::setup("nth_test_1", |dirs, sandbox| {
sandbox.with_files(vec![EmptyFile("notes.txt"), EmptyFile("arepas.txt")]);
let actual = nu!(
cwd: dirs.test(), pipeline(
r#"
ls
| sort-by name
| nth 0
| get name.0
"#
));
assert_eq!(actual.out, "arepas.txt");
});
}
#[test]
fn selects_many_rows() {
Playground::setup("nth_test_2", |dirs, sandbox| {
sandbox.with_files(vec![EmptyFile("notes.txt"), EmptyFile("arepas.txt")]);
let actual = nu!(
cwd: dirs.test(), pipeline(
r#"
ls
| get name
| nth 1 0
| length
"#
));
assert_eq!(actual.out, "2");
});
}

8
crates/nu-command/tests/commands/open.rs
View File

@ -59,7 +59,7 @@ fn parses_csv() {
fn parses_bson() {
let actual = nu!(
cwd: "tests/fixtures/formats",
"open sample.bson | get root | nth 0 | get b"
"open sample.bson | get root | select 0 | get b"
);
assert_eq!(actual.out, "hello");
@ -73,7 +73,7 @@ fn parses_more_bson_complexity() {
r#"
open sample.bson
| get root
| nth 6
| select 6
| get b
| get '$binary_subtype'
"#
@ -120,7 +120,7 @@ fn parses_more_bson_complexity() {
// `ints` has just `z`, and `floats` has only the column `f`. This means, in general, when working
// with sqlite, one will want to select a single table, e.g.:
//
// open sample.db | nth 1 | get table_values
// open sample.db | select 1 | get table_values
// ━━━┯━━━━━━
// # │ z
// ───┼──────
@ -139,7 +139,7 @@ fn parses_sqlite() {
r#"
open sample.db
| get table_values
| nth 2
| select 2
| get x
"#
));

2
crates/nu-command/tests/commands/parse.rs
View File

@ -25,7 +25,7 @@ mod simple {
open key_value_separated_arepa_ingredients.txt
| lines
| each { echo $it | parse "{Name}={Value}" }
| nth 1
| select 1
| get Value
"#
));

40
crates/nu-command/tests/commands/select.rs
View File

@ -1,4 +1,4 @@
use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
use nu_test_support::fs::Stub::{EmptyFile, FileWithContentToBeTrimmed};
use nu_test_support::playground::Playground;
use nu_test_support::{nu, pipeline};
@ -126,3 +126,41 @@ fn ignores_duplicate_columns_selected() {
assert_eq!(actual.out, "first name last name");
}
#[test]
fn selects_a_row() {
Playground::setup("select_test_1", |dirs, sandbox| {
sandbox.with_files(vec![EmptyFile("notes.txt"), EmptyFile("arepas.txt")]);
let actual = nu!(
cwd: dirs.test(), pipeline(
r#"
ls
| sort-by name
| select 0
| get name.0
"#
));
assert_eq!(actual.out, "arepas.txt");
});
}
#[test]
fn selects_many_rows() {
Playground::setup("select_test_2", |dirs, sandbox| {
sandbox.with_files(vec![EmptyFile("notes.txt"), EmptyFile("arepas.txt")]);
let actual = nu!(
cwd: dirs.test(), pipeline(
r#"
ls
| get name
| select 1 0
| length
"#
));
assert_eq!(actual.out, "2");
});
}

2
crates/nu-command/tests/format_conversions/sqlite.rs
View File

@ -11,7 +11,7 @@ fn table_to_sqlite_and_back_into_table() {
| to sqlite
| from sqlite
| get table_values
| nth 2
| select 2
| get x
"#
));

2
crates/nu-command/tests/format_conversions/tsv.rs
View File

@ -43,7 +43,7 @@ fn table_to_tsv_text() {
| last 1
| to tsv
| lines
| nth 1
| select 1
"#
));

6
crates/nu-protocol/src/value/mod.rs
View File

@ -564,7 +564,7 @@ impl Value {
Value::Nothing { span }
}
/// Follow a given column path into the value: for example accessing nth elements in a stream or list
/// Follow a given column path into the value: for example accessing select elements in a stream or list
pub fn follow_cell_path(self, cell_path: &[PathMember]) -> Result<Value, ShellError> {
let mut current = self;
for member in cell_path {
@ -575,7 +575,7 @@ impl Value {
val: count,
span: origin_span,
} => {
// Treat a numeric path member as `nth <val>`
// Treat a numeric path member as `select <val>`
match &mut current {
Value::List { vals: val, .. } => {
if let Some(item) = val.get(*count) {
@ -671,7 +671,7 @@ impl Value {
Ok(current)
}
/// Follow a given column path into the value: for example accessing nth elements in a stream or list
/// Follow a given column path into the value: for example accessing select elements in a stream or list
pub fn update_cell_path(
&mut self,
cell_path: &[PathMember],

2
docs/commands/lines.md
View File

@ -26,7 +26,7 @@ Basic usage:
One useful application is piping the contents of file into `lines`. This example extracts a certain line from a given file.
```shell
> cat lines.md | lines | nth 6
> cat lines.md | lines | select 6
## Examples
```

10
docs/commands/nth.md
View File

@ -1,12 +1,12 @@
# nth
This command returns the nth row of a table, starting from 0.
This command returns the select row of a table, starting from 0.
If the number given is less than 0 or more than the number of rows, nothing is returned.
## Usage
```shell
> [input-command] | nth <row number> ...args
> [input-command] | select <row number> ...args
```
## Parameters
@ -45,7 +45,7 @@ If the number given is less than 0 or more than the number of rows, nothing is r
```
```shell
> ls | nth 0
> ls | select 0
──────────┬────────────────────
name │ CODE_OF_CONDUCT.md
type │ File
@ -55,7 +55,7 @@ If the number given is less than 0 or more than the number of rows, nothing is r
```
```shell
> ls | nth 0 2
> ls | select 0 2
───┬────────────────────┬──────┬──────────┬─────────────
# │ name │ type │ size │ modified
───┼────────────────────┼──────┼──────────┼─────────────
@ -65,7 +65,7 @@ If the number given is less than 0 or more than the number of rows, nothing is r
```
```shell
> ls | nth 5
> ls | select 5
──────────┬───────────────
name │ Makefile.toml
type │ File