Struct RangeFrom 

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

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:

assert_eq!((2..), std::ops::RangeFrom { start: 2 });
assert_eq!(2 + 3 + 4, (2..).take(3).sum());

let arr = [0, 1, 2, 3, 4];
assert_eq!(arr[ ..  ], [0, 1, 2, 3, 4]);
assert_eq!(arr[ .. 3], [0, 1, 2      ]);
assert_eq!(arr[ ..=3], [0, 1, 2, 3   ]);
assert_eq!(arr[1..  ], [   1, 2, 3, 4]); // This is a `RangeFrom`
assert_eq!(arr[1.. 3], [   1, 2      ]);
assert_eq!(arr[1..=3], [   1, 2, 3   ]);

Fields

start: Idx

The lower bound of the range (inclusive).

Trait Implementations

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

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

Returns a duplicate of the value.

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

where Self:,

Performs copy-assignment from source.

impl<T> IntoBounds<T> for RangeFrom<T>

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).

impl<T> OneSidedRange<T> for RangeFrom<T>

where Self: RangeBounds<T>,

fn bound(self) -> (OneSidedRangeBound, T)

🔬This is a nightly-only experimental API. (one_sided_range #69780)

An internal-only helper function for split_off and split_off_mut that returns the bound of the one-sided range.

impl<Idx: PartialEq> PartialEq for RangeFrom<Idx>

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

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).

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

Start index bound.

fn end_bound(&self) -> Bound<&T>

End index bound.

fn contains<U>(&self, item: &U) -> bool

where T: PartialOrd<U>, U: ?Sized + PartialOrd<T>,

Returns true if item is contained in the range.

impl<T> RangeBounds<T> for RangeFrom<T>

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

Start index bound.

fn end_bound(&self) -> Bound<&T>

End index bound.

fn contains<U>(&self, item: &U) -> bool

where T: PartialOrd<U>, U: ?Sized + PartialOrd<T>,

Returns true if item is contained in the range.

impl<T> SliceIndex<[T]> for RangeFrom<usize>

The methods index and index_mut panic if the start of the range is out of bounds.

type Output = [T]

The output type returned by methods.

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.

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.

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.

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.

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.

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.

impl SliceIndex<str> for RangeFrom<usize>

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

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

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

type Output = str

The output type returned by methods.

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.

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.

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.

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.

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.

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.

impl<Idx> StructuralPartialEq for RangeFrom<Idx>