Trait TryFilter

pub trait TryFilter<O, E>: Sized {
    // Required methods
    fn try_filter_ok<F>(self, _: F) -> TryFilterOk<Self, F> 
       where F: FnMut(&O) -> Result<bool, E>;
    fn try_filter_err<F>(self, _: F) -> TryFilterErr<Self, F> 
       where F: FnMut(&E) -> Result<bool, E>;
}

Extension for Iterator<Item = Result<O, E>> to filter the Ok() and leaving the Err() as is, but allowing the filter to return a Result<bool, E> itself

Required Methods

fn try_filter_ok<F>(self, _: F) -> TryFilterOk<Self, F>

where F: FnMut(&O) -> Result<bool, E>,

Filters every Ok-value with a function that can return an Err. Useful when the filter condition uses functions that can fail.

 use resiter::try_filter::TryFilter;
 use std::str::FromStr;

 let v = ["1", "2", "4", "a", "5"]
     .iter()
     .map(Ok)
     .try_filter_ok(|e| usize::from_str(e).map(|n| n < 3))
     .collect::<Vec<Result<_, _>>>();

 assert_eq!(v.len(), 3);
 assert_eq!(v.iter().filter(|x| x.is_ok()).count(), 2);
 assert_eq!(v.iter().filter(|x| x.is_err()).count(), 1);

fn try_filter_err<F>(self, _: F) -> TryFilterErr<Self, F>

where F: FnMut(&E) -> Result<bool, E>,

Filters every Err-value with a function that can return an Err. Useful when the filter condition uses functions that can fail.

use resiter::try_filter::TryFilter;
use std::num::ParseIntError;
use std::str::FromStr;

let v = ["1", "2", "4", "a", "5"]
    .iter()
    .map(|txt| usize::from_str(txt))
    .try_filter_err(|_:&ParseIntError| Ok(false))
    .collect::<Vec<Result<_, _>>>();

assert_eq!(v.iter().filter(|x| x.is_ok()).count(), 4);
assert_eq!(v.iter().filter(|x| x.is_err()).count(), 0);

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<I, O, E> TryFilter<O, E> for I

where I: Iterator<Item = Result<O, E>> + Sized,