nu_command/matrix/
map.rs

1use crate::matrix::MatrixValue;
2use crate::matrix::value::value_to_f64;
3use ndarray::ArrayD;
4use nu_engine::ClosureEvalOnce;
5use nu_engine::command_prelude::*;
6use nu_protocol::engine::Closure;
7
8#[derive(Clone)]
9pub struct MatrixMap;
10
11impl Command for MatrixMap {
12    fn name(&self) -> &str {
13        "matrix map"
14    }
15
16    fn signature(&self) -> Signature {
17        Signature::build("matrix map")
18            .input_output_types(vec![(
19                Type::Custom("matrix".into()),
20                Type::Custom("matrix".into()),
21            )])
22            .required(
23                "closure",
24                SyntaxShape::Closure(Some(vec![SyntaxShape::Number])),
25                "The closure to apply to each element.",
26            )
27            .category(Category::Filters)
28    }
29
30    fn description(&self) -> &str {
31        "Apply a closure to each element of a matrix and return a new matrix."
32    }
33
34    fn search_terms(&self) -> Vec<&str> {
35        vec!["each", "apply", "element"]
36    }
37
38    fn run(
39        &self,
40        engine_state: &EngineState,
41        stack: &mut Stack,
42        call: &Call,
43        input: PipelineData,
44    ) -> Result<PipelineData, ShellError> {
45        let head = call.head;
46        let closure: Closure = call.req(engine_state, stack, 0)?;
47        let matrix = MatrixValue::from_value(&input.into_value(head)?)?;
48
49        let shape = matrix.array.shape().to_vec();
50        let mut vals = Vec::with_capacity(matrix.array.len());
51        for &val in matrix.array.iter() {
52            let element = Value::float(val, head);
53            let result = ClosureEvalOnce::new(engine_state, stack, closure.clone())
54                .run_with_value(element)?
55                .into_value(head)?;
56            vals.push(value_to_f64(&result, head).map_err(|_| {
57                ShellError::Generic(nu_protocol::shell_error::generic::GenericError::new(
58                    "Invalid result",
59                    "closure must return a number",
60                    head,
61                ))
62            })?);
63        }
64
65        let array = ArrayD::from_shape_vec(shape, vals).map_err(|e| {
66            ShellError::Generic(nu_protocol::shell_error::generic::GenericError::new(
67                "Reshape error",
68                e.to_string(),
69                head,
70            ))
71        })?;
72
73        Ok(MatrixValue::new(array)
74            .into_value(head)
75            .into_pipeline_data())
76    }
77
78    fn examples(&self) -> Vec<Example<'static>> {
79        vec![
80            Example {
81                description: "Double each element in a matrix",
82                example: "[[1 2] [3 4]] | into matrix | matrix map {|e| $e * 2} | matrix into-nu | to nuon",
83                result: Some(Value::test_string("[[2.0, 4.0], [6.0, 8.0]]")),
84            },
85            Example {
86                description: "Add 10 to each element of an identity matrix",
87                example: "matrix identity 2 | matrix map {|e| $e + 10} | matrix into-nu | to nuon",
88                result: Some(Value::test_string("[[11.0, 10.0], [10.0, 11.0]]")),
89            },
90        ]
91    }
92}
93
94#[cfg(test)]
95mod test {
96    use super::*;
97
98    #[test]
99    fn test_examples() -> nu_test_support::Result {
100        nu_test_support::test().examples(MatrixMap)
101    }
102}
nu_command/matrix/map.rs

nu_command/matrix/
map.rs
