Convert Result to Option: use ok().

let opt = res.ok();

Convert Option to Result: use ok_or().

let res = opt.ok_or("oh no");

Convert bool to Option: use then_some().

let res = boo.then_some(MyObject {});

Convert bool to Result: use then_some() and ok_or().

let res = boo.then_some(MyObject {}).ok_or(MyError {})

Convert Result to bool: use is_ok().

let boo = res.is_ok();

Convert Option to bool: use is_some() and is_none().

let is_some: bool = opt.is_some();
let is_none: bool = opt.is_none();

Convert str to String: use to_string().

let s: String = "str".to_string();

Convert String to number (f64, i32, etc): use String::parse.

let num = s.parse::<f64>()?;

1 ndarray conversions

Convert ndarray::ArrayView to ndarray::Array: use .to_owned().

Convert &[f64] to ndarray::ArrayView: use ArrayView3::from_shape.

let arr: ndarray::Array3<f64> = ArrayView3::from_shape((3, height, width), slice)?.to_owned();

2 nalgebra conversions

Convert &[f64] to na::DMatrixSlice: use from_slice_with_strides