Trait sp_std::iter::Sum1.12.0[][src]

pub trait Sum<A = Self> {
    pub fn sum<I>(iter: I) -> Self
    where
        I: Iterator<Item = A>
; }

Trait to represent types that can be created by summing up an iterator.

This trait is used to implement the sum() method on iterators. Types which implement the trait can be generated by the sum() method. Like FromIterator this trait should rarely be called directly and instead interacted with through Iterator::sum().

Required methods

pub fn sum<I>(iter: I) -> Self where
    I: Iterator<Item = A>, 
[src]

Method which takes an iterator and generates Self from the elements by "summing up" the items.

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Implementations on Foreign Types

impl Sum<i16> for i16[src]

impl<'a> Sum<&'a f32> for f32[src]

impl Sum<i128> for i128[src]

impl Sum<i64> for i64[src]

impl<'a> Sum<&'a u128> for u128[src]

impl<'a> Sum<&'a u8> for u8[src]

impl Sum<isize> for isize[src]

impl<'a> Sum<&'a i64> for i64[src]

impl Sum<f64> for f64[src]

impl<'a> Sum<&'a Duration> for Duration[src]

impl<'a> Sum<&'a f64> for f64[src]

impl Sum<f32> for f32[src]

impl<'a> Sum<&'a u32> for u32[src]

impl<'a> Sum<&'a u64> for u64[src]

impl<'a> Sum<&'a usize> for usize[src]

impl Sum<u64> for u64[src]

impl Sum<i32> for i32[src]

impl<T, U> Sum<Option<U>> for Option<T> where
    T: Sum<U>, 
[src]

pub fn sum<I>(iter: I) -> Option<T> where
    I: Iterator<Item = Option<U>>, 
[src]

Takes each element in the Iterator: if it is a None, no further elements are taken, and the None is returned. Should no None occur, the sum of all elements is returned.

Examples

This sums up the position of the character 'a' in a vector of strings, if a word did not have the character 'a' the operation returns None:

let words = vec!["have", "a", "great", "day"];
let total: Option<usize> = words.iter().map(|w| w.find('a')).sum();
assert_eq!(total, Some(5));

impl Sum<u32> for u32[src]

impl Sum<i8> for i8[src]

impl<'a> Sum<&'a i16> for i16[src]

impl Sum<u16> for u16[src]

impl Sum<usize> for usize[src]

impl<'a> Sum<&'a isize> for isize[src]

impl<'a> Sum<&'a i128> for i128[src]

impl Sum<Duration> for Duration[src]

impl<'a> Sum<&'a i8> for i8[src]

impl Sum<u128> for u128[src]

impl<'a> Sum<&'a u16> for u16[src]

impl Sum<u8> for u8[src]

impl<'a> Sum<&'a i32> for i32[src]

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Implementors

impl Sum<Wrapping<i8>> for Wrapping<i8>1.14.0[src]

impl Sum<Wrapping<i16>> for Wrapping<i16>1.14.0[src]

impl Sum<Wrapping<i32>> for Wrapping<i32>1.14.0[src]

impl Sum<Wrapping<i64>> for Wrapping<i64>1.14.0[src]

impl Sum<Wrapping<i128>> for Wrapping<i128>1.14.0[src]

impl Sum<Wrapping<isize>> for Wrapping<isize>1.14.0[src]

impl Sum<Wrapping<u8>> for Wrapping<u8>1.14.0[src]

impl Sum<Wrapping<u16>> for Wrapping<u16>1.14.0[src]

impl Sum<Wrapping<u32>> for Wrapping<u32>1.14.0[src]

impl Sum<Wrapping<u64>> for Wrapping<u64>1.14.0[src]

impl Sum<Wrapping<u128>> for Wrapping<u128>1.14.0[src]

impl Sum<Wrapping<usize>> for Wrapping<usize>1.14.0[src]

impl<'a> Sum<&'a Wrapping<i8>> for Wrapping<i8>1.14.0[src]

impl<'a> Sum<&'a Wrapping<i16>> for Wrapping<i16>1.14.0[src]

impl<'a> Sum<&'a Wrapping<i32>> for Wrapping<i32>1.14.0[src]

impl<'a> Sum<&'a Wrapping<i64>> for Wrapping<i64>1.14.0[src]

impl<'a> Sum<&'a Wrapping<i128>> for Wrapping<i128>1.14.0[src]

impl<'a> Sum<&'a Wrapping<isize>> for Wrapping<isize>1.14.0[src]

impl<'a> Sum<&'a Wrapping<u8>> for Wrapping<u8>1.14.0[src]

impl<'a> Sum<&'a Wrapping<u16>> for Wrapping<u16>1.14.0[src]

impl<'a> Sum<&'a Wrapping<u32>> for Wrapping<u32>1.14.0[src]

impl<'a> Sum<&'a Wrapping<u64>> for Wrapping<u64>1.14.0[src]

impl<'a> Sum<&'a Wrapping<u128>> for Wrapping<u128>1.14.0[src]

impl<'a> Sum<&'a Wrapping<usize>> for Wrapping<usize>1.14.0[src]

impl<T, U, E> Sum<Result<U, E>> for Result<T, E> where
    T: Sum<U>, 
1.16.0[src]

pub fn sum<I>(iter: I) -> Result<T, E> where
    I: Iterator<Item = Result<U, E>>, 
[src]

Takes each element in the Iterator: if it is an Err, no further elements are taken, and the Err is returned. Should no Err occur, the sum of all elements is returned.

Examples

This sums up every integer in a vector, rejecting the sum if a negative element is encountered:

let v = vec![1, 2];
let res: Result<i32, &'static str> = v.iter().map(|&x: &i32|
    if x < 0 { Err("Negative element found") }
    else { Ok(x) }
).sum();
assert_eq!(res, Ok(3));
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