# Struct RangeFrom

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    pub struct RangeFrom<Idx> {
        pub start: Idx,
    }

🔬This is a nightly-only experimental API. (`new_range_api` #125687)
Expand description

A range only bounded inclusively below (`start..`).

The `RangeFrom` `start..` contains all values with `x >= start`.

Note: Overflow in the `Iterator` implementation (when the contained data type reaches its numerical limit) is allowed to panic, wrap, or saturate. This behavior is defined by the implementation of the `Step` trait. For primitive integers, this follows the normal rules, and respects the overflow checks profile (panic in debug, wrap in release). Note also that overflow happens earlier than you might assume: the overflow happens in the call to `next` that yields the maximum value, as the range must be set to a state to yield the next value.

## §Examples

The `start..` syntax is a `RangeFrom`:

    #![feature(new_range_api)]
    use core::range::RangeFrom;

    assert_eq!(RangeFrom::from(2..), core::range::RangeFrom { start: 2 });
    assert_eq!(2 + 3 + 4, RangeFrom::from(2..).into_iter().take(3).sum());

## Fields§

§`start: Idx`
🔬This is a nightly-only experimental API. (`new_range_api` #125687)

The lower bound of the range (inclusive).

## Implementations§

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### impl<Idx: Step> RangeFrom<Idx>

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#### pub fn iter(&self) -> IterRangeFrom<Idx> ⓘ

🔬This is a nightly-only experimental API. (`new_range_api` #125687)

Creates an iterator over the elements within this range.

Shorthand for `.clone().into_iter()`

##### §Examples

    #![feature(new_range_api)]
    use core::range::RangeFrom;

    let mut i = RangeFrom::from(3..).iter().map(|n| n*n);
    assert_eq!(i.next(), Some(9));
    assert_eq!(i.next(), Some(16));
    assert_eq!(i.next(), Some(25));

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### impl<Idx: PartialOrd<Idx>> RangeFrom<Idx>

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

🔬This is a nightly-only experimental API. (`new_range_api` #125687)

Returns `true` if `item` is contained in the range.

##### §Examples

    #![feature(new_range_api)]
    use core::range::RangeFrom;

    assert!(!RangeFrom::from(3..).contains(&2));
    assert!( RangeFrom::from(3..).contains(&3));
    assert!( RangeFrom::from(3..).contains(&1_000_000_000));

    assert!( RangeFrom::from(0.0..).contains(&0.5));
    assert!(!RangeFrom::from(0.0..).contains(&f32::NAN));
    assert!(!RangeFrom::from(f32::NAN..).contains(&0.5));

## Trait Implementations§

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### impl<Idx: Clone> Clone for RangeFrom<Idx>

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#### fn clone(&self) -> RangeFrom<Idx>

Returns a duplicate of the value. Read more
1.0.0 · Source§

#### fn clone_from(&mut self, source: &Self)
where Self:,

Performs copy-assignment from `source`. Read more
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### impl<Idx: Debug> Debug for RangeFrom<Idx>

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#### fn fmt(&self, fmt: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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### impl<T> From<RangeFrom<T>> for RangeFrom<T>

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#### fn from(value: RangeFrom<T>) -> Self

Converts to this type from the input type.
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### impl<T> From<RangeFrom<T>> for RangeFrom<T>

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#### fn from(value: RangeFrom<T>) -> Self

Converts to this type from the input type.
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### impl<Idx: Hash> Hash for RangeFrom<Idx>

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#### fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given `Hasher`. Read more
1.3.0 · Source§

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

Feeds a slice of this type into the given `Hasher`. Read more
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### impl<T> IntoBounds<T> for RangeFrom<T>

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#### fn into_bounds(self) -> (Bound<T>, Bound<T>)

🔬This is a nightly-only experimental API. (`range_into_bounds` #136903)
Convert this range into the start and end bounds. Returns `(start_bound, end_bound)`. Read more
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#### fn intersect<R>(self, other: R) -> (Bound<T>, Bound<T>)
where Self: Sized, T: Ord, R: Sized + IntoBounds<T>,

🔬This is a nightly-only experimental API. (`range_into_bounds` #136903)
Compute the intersection of `self` and `other`. Read more
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### impl<A: Step> IntoIterator for RangeFrom<A>

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#### type Item = A

The type of the elements being iterated over.
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#### type IntoIter = IterRangeFrom<A>

Which kind of iterator are we turning this into?
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#### fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value. Read more
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### impl<Idx: PartialEq> PartialEq for RangeFrom<Idx>

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#### fn eq(&self, other: &RangeFrom<Idx>) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
1.0.0 · Source§

#### fn ne(&self, other: &Rhs) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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### impl<T> RangeBounds<T> for RangeFrom<&T>

If you need to use this implementation where `T` is unsized, consider using the `RangeBounds` impl for a 2-tuple of `Bound<&T>`, i.e. replace `start..` with `(Bound::Included(start), Bound::Unbounded)`.

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#### fn start_bound(&self) -> Bound<&T>

Start index bound. Read more
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#### fn end_bound(&self) -> Bound<&T>

End index bound. Read more
1.35.0 · Source§

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

Returns `true` if `item` is contained in the range. Read more
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#### fn is_empty(&self) -> bool
where T: PartialOrd,

🔬This is a nightly-only experimental API. (`range_bounds_is_empty` #137300)
Returns `true` if the range contains no items. One-sided ranges (`RangeFrom`, etc) always return `false`. Read more
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### impl<T> RangeBounds<T> for RangeFrom<T>

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#### fn start_bound(&self) -> Bound<&T>

Start index bound. Read more
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#### fn end_bound(&self) -> Bound<&T>

End index bound. Read more
1.35.0 · Source§

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

Returns `true` if `item` is contained in the range. Read more
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#### fn is_empty(&self) -> bool
where T: PartialOrd,

🔬This is a nightly-only experimental API. (`range_bounds_is_empty` #137300)
Returns `true` if the range contains no items. One-sided ranges (`RangeFrom`, etc) always return `false`. Read more
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### impl<T> SliceIndex<[T]> for RangeFrom<usize>

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#### type Output = [T]

The output type returned by methods.
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#### fn get(self, slice: &[T]) -> Option<&[T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
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#### fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
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#### unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
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#### unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
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#### fn index(self, slice: &[T]) -> &[T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
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#### fn index_mut(self, slice: &mut [T]) -> &mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
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### impl SliceIndex<ByteStr> for RangeFrom<usize>

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#### type Output = ByteStr

The output type returned by methods.
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#### fn get(self, slice: &ByteStr) -> Option<&Self::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
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#### fn get_mut(self, slice: &mut ByteStr) -> Option<&mut Self::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
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#### unsafe fn get_unchecked(self, slice: *const ByteStr) -> *const Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
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#### unsafe fn get_unchecked_mut(self, slice: *mut ByteStr) -> *mut Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
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#### fn index(self, slice: &ByteStr) -> &Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
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#### fn index_mut(self, slice: &mut ByteStr) -> &mut Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
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### impl SliceIndex<str> for RangeFrom<usize>

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#### type Output = str

The output type returned by methods.
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#### fn get(self, slice: &str) -> Option<&Self::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
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#### fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
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#### unsafe fn get_unchecked(self, slice: *const str) -> *const Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### unsafe fn get_unchecked_mut(self, slice: *mut str) -> *mut Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
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#### fn index(self, slice: &str) -> &Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
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#### fn index_mut(self, slice: &mut str) -> &mut Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
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### impl<Idx: Copy> Copy for RangeFrom<Idx>

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### impl<Idx: Eq> Eq for RangeFrom<Idx>

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### impl<Idx> StructuralPartialEq for RangeFrom<Idx>

## Auto Trait Implementations§

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### impl<Idx> Freeze for RangeFrom<Idx>
where Idx: Freeze,

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### impl<Idx> RefUnwindSafe for RangeFrom<Idx>
where Idx: RefUnwindSafe,

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### impl<Idx> Send for RangeFrom<Idx>
where Idx: Send,

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### impl<Idx> Sync for RangeFrom<Idx>
where Idx: Sync,

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### impl<Idx> Unpin for RangeFrom<Idx>
where Idx: Unpin,

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### impl<Idx> UnwindSafe for RangeFrom<Idx>
where Idx: UnwindSafe,

## Blanket Implementations§

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### impl<T> Any for T
where T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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### impl<T> Borrow<T> for T
where T: ?Sized,

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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for T
where T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<T> CloneToUninit for T
where T: Clone,

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#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit` #126799)
Performs copy-assignment from `self` to `dest`. Read more
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### impl<T> From<T> for T

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#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T, U> Into<U> for T
where U: From<T>,

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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T, U> TryFrom<U> for T
where U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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### impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.