mirror of
https://github.com/nushell/nushell
synced 2025-01-08 19:29:08 +00:00
220b105efb
# Description
While perusing Value.rs, I noticed the `Value::int()`, `Value::float()`,
`Value::boolean()` and `Value::string()` constructors, which seem
designed to make it easier to construct various Values, but which aren't
used often at all in the codebase. So, using a few find-replaces
regexes, I increased their usage. This reduces overall LOC because
structures like this:
```
Value::Int {
val: a,
span: head
}
```
are changed into
```
Value::int(a, head)
```
and are respected as such by the project's formatter.
There are little readability concerns because the second argument to all
of these is `span`, and it's almost always extremely obvious which is
the span at every callsite.
# User-Facing Changes
None.
# Tests + Formatting
Don't forget to add tests that cover your changes.
Make sure you've run and fixed any issues with these commands:
- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass
# After Submitting
If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.
93 lines
2.9 KiB
Rust
93 lines
2.9 KiB
Rust
use super::variance::compute_variance as variance;
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use crate::math::utils::run_with_function;
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use nu_protocol::ast::Call;
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use nu_protocol::engine::{Command, EngineState, Stack};
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use nu_protocol::{Category, Example, PipelineData, ShellError, Signature, Span, Type, Value};
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#[derive(Clone)]
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pub struct SubCommand;
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impl Command for SubCommand {
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fn name(&self) -> &str {
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"math stddev"
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}
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fn signature(&self) -> Signature {
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Signature::build("math stddev")
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.input_output_types(vec![(Type::List(Box::new(Type::Number)), Type::Number)])
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.switch(
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"sample",
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"calculate sample standard deviation (i.e. using N-1 as the denominator)",
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Some('s'),
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)
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.category(Category::Math)
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}
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fn usage(&self) -> &str {
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"Returns the standard deviation of a list of numbers, or of each column in a table"
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}
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fn search_terms(&self) -> Vec<&str> {
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vec![
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"SD",
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"standard",
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"deviation",
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"dispersion",
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"variation",
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"statistics",
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]
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}
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fn run(
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&self,
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_engine_state: &EngineState,
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_stack: &mut Stack,
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call: &Call,
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input: PipelineData,
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) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
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let sample = call.has_flag("sample");
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run_with_function(call, input, compute_stddev(sample))
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}
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fn examples(&self) -> Vec<Example> {
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vec![
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Example {
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description: "Compute the standard deviation of a list of numbers",
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example: "[1 2 3 4 5] | math stddev",
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result: Some(Value::float(std::f64::consts::SQRT_2, Span::test_data())),
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},
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Example {
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description: "Compute the sample standard deviation of a list of numbers",
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example: "[1 2 3 4 5] | math stddev -s",
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result: Some(Value::float(1.5811388300841898, Span::test_data())),
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},
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]
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}
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}
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pub fn compute_stddev(sample: bool) -> impl Fn(&[Value], &Span) -> Result<Value, ShellError> {
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move |values: &[Value], span: &Span| {
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let variance = variance(sample)(values, span);
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match variance {
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Ok(Value::Float { val, span }) => Ok(Value::Float { val: val.sqrt(), span }),
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Ok(Value::Int { val, span }) => Ok(Value::Float { val: (val as f64).sqrt(), span }),
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Err(ShellError::UnsupportedInput(_, err_span)) => Err(ShellError::UnsupportedInput(
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"Attempted to compute the standard deviation with an item that cannot be used for that.".to_string(),
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err_span,
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)),
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other => other
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}
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}
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}
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#[cfg(test)]
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mod test {
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use super::*;
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#[test]
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fn test_examples() {
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use crate::test_examples;
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test_examples(SubCommand {})
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}
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}
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