Trait enso_prelude::iter::Sum 1.12.0[−][src]
Expand description
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
fn sum<I>(iter: I) -> Self where
I: Iterator<Item = A>,
[src]
I: Iterator<Item = A>,
Expand description
Method which takes an iterator and generates Self
from the elements by
“summing up” the items.
Implementations on Foreign Types
impl<T, U, E> Sum<Result<U, E>> for Result<T, E> where
T: Sum<U>,
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impl<T, U, E> Sum<Result<U, E>> for Result<T, E> where
T: Sum<U>,
[src]pub fn sum<I>(iter: I) -> Result<T, E> where
I: Iterator<Item = Result<U, E>>,
[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));
impl<T, U> Sum<Option<U>> for Option<T> where
T: Sum<U>,
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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]
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<N, C> Sum<Matrix<N, Dynamic, C, <DefaultAllocator as Allocator<N, Dynamic, C>>::Buffer>> for Matrix<N, Dynamic, C, <DefaultAllocator as Allocator<N, Dynamic, C>>::Buffer> where
C: Dim,
N: Scalar + ClosedAdd<N> + Zero,
DefaultAllocator: Allocator<N, Dynamic, C>,
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impl<N, C> Sum<Matrix<N, Dynamic, C, <DefaultAllocator as Allocator<N, Dynamic, C>>::Buffer>> for Matrix<N, Dynamic, C, <DefaultAllocator as Allocator<N, Dynamic, C>>::Buffer> where
C: Dim,
N: Scalar + ClosedAdd<N> + Zero,
DefaultAllocator: Allocator<N, Dynamic, C>,
[src]pub fn sum<I>(
iter: I
) -> Matrix<N, Dynamic, C, <DefaultAllocator as Allocator<N, Dynamic, C>>::Buffer> where
I: Iterator<Item = Matrix<N, Dynamic, C, <DefaultAllocator as Allocator<N, Dynamic, C>>::Buffer>>,
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pub fn sum<I>(
iter: I
) -> Matrix<N, Dynamic, C, <DefaultAllocator as Allocator<N, Dynamic, C>>::Buffer> where
I: Iterator<Item = Matrix<N, Dynamic, C, <DefaultAllocator as Allocator<N, Dynamic, C>>::Buffer>>,
[src]Example
assert_eq!(vec![DVector::repeat(3, 1.0f64), DVector::repeat(3, 1.0f64), DVector::repeat(3, 1.0f64)].into_iter().sum::<DVector<f64>>(), DVector::repeat(3, 1.0f64) + DVector::repeat(3, 1.0f64) + DVector::repeat(3, 1.0f64));
Panics
Panics if the iterator is empty:
iter::empty::<DMatrix<f64>>().sum::<DMatrix<f64>>(); // panics!
impl<'a, N, C> Sum<&'a Matrix<N, Dynamic, C, <DefaultAllocator as Allocator<N, Dynamic, C>>::Buffer>> for Matrix<N, Dynamic, C, <DefaultAllocator as Allocator<N, Dynamic, C>>::Buffer> where
C: Dim,
N: Scalar + ClosedAdd<N> + Zero,
DefaultAllocator: Allocator<N, Dynamic, C>,
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impl<'a, N, C> Sum<&'a Matrix<N, Dynamic, C, <DefaultAllocator as Allocator<N, Dynamic, C>>::Buffer>> for Matrix<N, Dynamic, C, <DefaultAllocator as Allocator<N, Dynamic, C>>::Buffer> where
C: Dim,
N: Scalar + ClosedAdd<N> + Zero,
DefaultAllocator: Allocator<N, Dynamic, C>,
[src]impl<N, R, C> Sum<Matrix<N, R, C, <DefaultAllocator as Allocator<N, R, C>>::Buffer>> for Matrix<N, R, C, <DefaultAllocator as Allocator<N, R, C>>::Buffer> where
C: DimName,
R: DimName,
N: Scalar + ClosedAdd<N> + Zero,
DefaultAllocator: Allocator<N, R, C>,
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impl<N, R, C> Sum<Matrix<N, R, C, <DefaultAllocator as Allocator<N, R, C>>::Buffer>> for Matrix<N, R, C, <DefaultAllocator as Allocator<N, R, C>>::Buffer> where
C: DimName,
R: DimName,
N: Scalar + ClosedAdd<N> + Zero,
DefaultAllocator: Allocator<N, R, C>,
[src]impl<'a, N, R, C> Sum<&'a Matrix<N, R, C, <DefaultAllocator as Allocator<N, R, C>>::Buffer>> for Matrix<N, R, C, <DefaultAllocator as Allocator<N, R, C>>::Buffer> where
C: DimName,
R: DimName,
N: Scalar + ClosedAdd<N> + Zero,
DefaultAllocator: Allocator<N, R, C>,
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impl<'a, N, R, C> Sum<&'a Matrix<N, R, C, <DefaultAllocator as Allocator<N, R, C>>::Buffer>> for Matrix<N, R, C, <DefaultAllocator as Allocator<N, R, C>>::Buffer> where
C: DimName,
R: DimName,
N: Scalar + ClosedAdd<N> + Zero,
DefaultAllocator: Allocator<N, R, C>,
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