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/Rust

Struct std::ops::RangeTo

pub struct RangeTo<Idx> {
    pub end: Idx,
}

A range only bounded exclusively above (..end).

The RangeTo ..end contains all values with x < end. It cannot serve as an Iterator because it doesn't have a starting point.

Examples

The ..end syntax is a RangeTo:

assert_eq!((..5), std::ops::RangeTo { end: 5 });

It does not have an IntoIterator implementation, so you can't use it in a for loop directly. This won't compile:

ⓘThis example deliberately fails to compile
// error[E0277]: the trait bound `std::ops::RangeTo<{integer}>:
// std::iter::Iterator` is not satisfied
for i in ..5 {
    // ...
}

When used as a slicing index, RangeTo produces a slice of all array elements before the index indicated by end.

let arr = [0, 1, 2, 3, 4];
assert_eq!(arr[ ..  ], [0,1,2,3,4]);
assert_eq!(arr[ .. 3], [0,1,2    ]);  // RangeTo
assert_eq!(arr[ ..=3], [0,1,2,3  ]);
assert_eq!(arr[1..  ], [  1,2,3,4]);
assert_eq!(arr[1.. 3], [  1,2    ]);
assert_eq!(arr[1..=3], [  1,2,3  ]);

Fields

end: Idx

The upper bound of the range (exclusive).

Methods

impl<Idx> RangeTo<Idx> where
    Idx: PartialOrd<Idx>, [src]

pub fn contains<U>(&self, item: &U) -> bool where
    Idx: PartialOrd<U>,
    U: PartialOrd<Idx> + ?Sized, [src]1.35.0

Returns true if item is contained in the range.

Examples

use std::f32;

assert!( (..5).contains(&-1_000_000_000));
assert!( (..5).contains(&4));
assert!(!(..5).contains(&5));

assert!( (..1.0).contains(&0.5));
assert!(!(..1.0).contains(&f32::NAN));
assert!(!(..f32::NAN).contains(&0.5));

Trait Implementations

impl<Idx> Copy for RangeTo<Idx> where
    Idx: Copy, [src]

impl<Idx> Hash for RangeTo<Idx> where
    Idx: Hash, [src]

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, [src]1.3.0

Feeds a slice of this type into the given [Hasher]. Read more

impl<Idx> Clone for RangeTo<Idx> where
    Idx: Clone, [src]

fn clone_from(&mut self, source: &Self)[src]

Performs copy-assignment from source. Read more

impl<Idx> Eq for RangeTo<Idx> where
    Idx: Eq, [src]

impl<Idx> Debug for RangeTo<Idx> where
    Idx: Debug, [src]

impl<Idx> PartialEq<RangeTo<Idx>> for RangeTo<Idx> where
    Idx: PartialEq<Idx>, [src]

impl SliceIndex<str> for RangeTo<usize>[src]1.20.0

Implements substring slicing with syntax &self[.. end] or &mut self[.. end].

Returns a slice of the given string from the byte range [0, end). Equivalent to &self[0 .. end] or &mut self[0 .. end].

This operation is O(1).

Prior to 1.20.0, these indexing operations were still supported by direct implementation of Index and IndexMut.

Panics

Panics if end does not point to the starting byte offset of a character (as defined by is_char_boundary), or if end > len.

type Output = str

The output type returned by methods.

impl<T> SliceIndex<[T]> for RangeTo<usize>[src]1.15.0

type Output = [T]

The output type returned by methods.

ⓘImportant traits for &'_ [u8]
impl<'_> Read for &'_ [u8]
impl<'_> Write for &'_ mut [u8]
ⓘImportant traits for &'_ [u8]
impl<'_> Read for &'_ [u8]
impl<'_> Write for &'_ mut [u8]
ⓘImportant traits for &'_ [u8]
impl<'_> Read for &'_ [u8]
impl<'_> Write for &'_ mut [u8]
ⓘImportant traits for &'_ [u8]
impl<'_> Read for &'_ [u8]
impl<'_> Write for &'_ mut [u8]

impl<'_, T> RangeBounds<T> for RangeTo<&'_ T>[src]1.28.0

fn contains<U>(&self, item: &U) -> bool where
    T: PartialOrd<U>,
    U: PartialOrd<T> + ?Sized, [src]1.35.0

Returns true if item is contained in the range. Read more

impl<T> RangeBounds<T> for RangeTo<T>[src]1.28.0

fn contains<U>(&self, item: &U) -> bool where
    T: PartialOrd<U>,
    U: PartialOrd<T> + ?Sized, [src]1.35.0

Returns true if item is contained in the range. Read more

impl Index<RangeTo<usize>> for String[src]

type Output = str

The returned type after indexing.

impl IndexMut<RangeTo<usize>> for String[src]1.3.0

Auto Trait Implementations

impl<Idx> UnwindSafe for RangeTo<Idx> where
    Idx: UnwindSafe, 

impl<Idx> RefUnwindSafe for RangeTo<Idx> where
    Idx: RefUnwindSafe, 

impl<Idx> Unpin for RangeTo<Idx> where
    Idx: Unpin, 

impl<Idx> Send for RangeTo<Idx> where
    Idx: Send, 

impl<Idx> Sync for RangeTo<Idx> where
    Idx: Sync, 

Blanket Implementations

impl<T, U> TryFrom<U> for T where
    U: Into<T>, [src]

type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> Into<U> for T where
    U: From<T>, [src]

impl<T> From<T> for T[src]

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, [src]

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

impl<T> Borrow<T> for T where
    T: ?Sized, [src]

ⓘImportant traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
    F: Unpin + Future + ?Sized, 
    type Output = <F as Future>::Output;
impl<'_, I> Iterator for &'_ mut I where
    I: Iterator + ?Sized, 
    type Item = <I as Iterator>::Item;
impl<'_, R: Read + ?Sized> Read for &'_ mut R
impl<'_, W: Write + ?Sized> Write for &'_ mut W

impl<T> BorrowMut<T> for T where
    T: ?Sized, [src]

ⓘImportant traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
    F: Unpin + Future + ?Sized, 
    type Output = <F as Future>::Output;
impl<'_, I> Iterator for &'_ mut I where
    I: Iterator + ?Sized, 
    type Item = <I as Iterator>::Item;
impl<'_, R: Read + ?Sized> Read for &'_ mut R
impl<'_, W: Write + ?Sized> Write for &'_ mut W

impl<T> Any for T where
    T: 'static + ?Sized, [src]

impl<T> ToOwned for T where
    T: Clone, [src]

type Owned = T

The resulting type after obtaining ownership.

© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/ops/struct.RangeTo.html