pub trait Index<Idx>where
Idx: ?Sized,{
type Output: ?Sized;
// Required method
fn index(&self, index: Idx) -> &Self::Output;
}
miri-test-libstd
only.Expand description
Used for indexing operations (container[index]
) in immutable contexts.
container[index]
is actually syntactic sugar for *container.index(index)
,
but only when used as an immutable value. If a mutable value is requested,
IndexMut
is used instead. This allows nice things such as
let value = v[index]
if the type of value
implements Copy
.
Examples
The following example implements Index
on a read-only NucleotideCount
container, enabling individual counts to be retrieved with index syntax.
use std::ops::Index;
enum Nucleotide {
A,
C,
G,
T,
}
struct NucleotideCount {
a: usize,
c: usize,
g: usize,
t: usize,
}
impl Index<Nucleotide> for NucleotideCount {
type Output = usize;
fn index(&self, nucleotide: Nucleotide) -> &Self::Output {
match nucleotide {
Nucleotide::A => &self.a,
Nucleotide::C => &self.c,
Nucleotide::G => &self.g,
Nucleotide::T => &self.t,
}
}
}
let nucleotide_count = NucleotideCount {a: 14, c: 9, g: 10, t: 12};
assert_eq!(nucleotide_count[Nucleotide::A], 14);
assert_eq!(nucleotide_count[Nucleotide::C], 9);
assert_eq!(nucleotide_count[Nucleotide::G], 10);
assert_eq!(nucleotide_count[Nucleotide::T], 12);
Required Associated Types§
Required Methods§
Implementors§
source§impl Index<usize> for FixedBitSet
impl Index<usize> for FixedBitSet
Return true if the bit is enabled in the bitset, or false otherwise.
Note: bits outside the capacity are always disabled, and thus indexing a FixedBitSet will not panic.
§impl Index<Range<usize>> for UninitSlice
impl Index<Range<usize>> for UninitSlice
type Output = UninitSlice
§impl Index<RangeFrom<usize>> for UninitSlice
impl Index<RangeFrom<usize>> for UninitSlice
type Output = UninitSlice
§impl Index<RangeFull> for UninitSlice
impl Index<RangeFull> for UninitSlice
type Output = UninitSlice
§impl Index<RangeInclusive<usize>> for UninitSlice
impl Index<RangeInclusive<usize>> for UninitSlice
type Output = UninitSlice
§impl Index<RangeTo<usize>> for UninitSlice
impl Index<RangeTo<usize>> for UninitSlice
type Output = UninitSlice
§impl Index<RangeToInclusive<usize>> for UninitSlice
impl Index<RangeToInclusive<usize>> for UninitSlice
type Output = UninitSlice
§impl<'s, T, I> Index<I> for SliceVec<'s, T>where
I: SliceIndex<[T]>,
impl<'s, T, I> Index<I> for SliceVec<'s, T>where I: SliceIndex<[T]>,
type Output = <I as SliceIndex<[T]>>::Output
§impl<A, I> Index<I> for ArrayVec<A>where
A: Array,
I: SliceIndex<[<A as Array>::Item]>,
impl<A, I> Index<I> for ArrayVec<A>where A: Array, I: SliceIndex<[<A as Array>::Item]>,
type Output = <I as SliceIndex<[<A as Array>::Item]>>::Output
§impl<A, I> Index<I> for SmallVec<A>where
A: Array,
I: SliceIndex<[<A as Array>::Item]>,
impl<A, I> Index<I> for SmallVec<A>where A: Array, I: SliceIndex<[<A as Array>::Item]>,
type Output = <I as SliceIndex<[<A as Array>::Item]>>::Output
§impl<A, I> Index<I> for TinyVec<A>where
A: Array,
I: SliceIndex<[<A as Array>::Item]>,
impl<A, I> Index<I> for TinyVec<A>where A: Array, I: SliceIndex<[<A as Array>::Item]>,
type Output = <I as SliceIndex<[<A as Array>::Item]>>::Output
§impl<AllocU32> Index<BucketPopIndex> for EntropyBucketPopulation<AllocU32>where
AllocU32: Allocator<u32>,
impl<AllocU32> Index<BucketPopIndex> for EntropyBucketPopulation<AllocU32>where AllocU32: Allocator<u32>,
const: unstable · source§impl<I> Index<I> for strwhere
I: SliceIndex<str>,
impl<I> Index<I> for strwhere I: SliceIndex<str>,
type Output = <I as SliceIndex<str>>::Output
source§impl<I, T, const LANES: usize> Index<I> for Simd<T, LANES>where
T: SimdElement,
LaneCount<LANES>: SupportedLaneCount,
I: SliceIndex<[T]>,
impl<I, T, const LANES: usize> Index<I> for Simd<T, LANES>where T: SimdElement, LaneCount<LANES>: SupportedLaneCount, I: SliceIndex<[T]>,
type Output = <I as SliceIndex<[T]>>::Output
source§impl<K, Q, V, A> Index<&Q> for BTreeMap<K, V, A>where
A: Allocator + Clone,
K: Borrow<Q> + Ord,
Q: Ord + ?Sized,
impl<K, Q, V, A> Index<&Q> for BTreeMap<K, V, A>where A: Allocator + Clone, K: Borrow<Q> + Ord, Q: Ord + ?Sized,
source§impl<K, Q, V, S> Index<&Q> for kvarn::prelude::HashMap<K, V, S>where
K: Eq + Hash + Borrow<Q>,
Q: Eq + Hash + ?Sized,
S: BuildHasher,
impl<K, Q, V, S> Index<&Q> for kvarn::prelude::HashMap<K, V, S>where K: Eq + Hash + Borrow<Q>, Q: Eq + Hash + ?Sized, S: BuildHasher,
§impl<K, Q, V, S, A> Index<&Q> for HashMap<K, V, S, A>where
K: Eq + Hash + Borrow<Q>,
Q: Eq + Hash + ?Sized,
S: BuildHasher,
A: Allocator + Clone,
impl<K, Q, V, S, A> Index<&Q> for HashMap<K, V, S, A>where K: Eq + Hash + Borrow<Q>, Q: Eq + Hash + ?Sized, S: BuildHasher, A: Allocator + Clone,
§impl<K, Q, V, S, A> Index<&Q> for HashMap<K, V, S, A>where
K: Eq + Hash,
Q: Hash + Equivalent<K> + ?Sized,
S: BuildHasher,
A: Allocator + Clone,
impl<K, Q, V, S, A> Index<&Q> for HashMap<K, V, S, A>where K: Eq + Hash, Q: Hash + Equivalent<K> + ?Sized, S: BuildHasher, A: Allocator + Clone,
source§impl<K, V, Q, S> Index<&Q> for IndexMap<K, V, S>where
Q: Hash + Equivalent<K> + ?Sized,
K: Hash + Eq,
S: BuildHasher,
impl<K, V, Q, S> Index<&Q> for IndexMap<K, V, S>where Q: Hash + Equivalent<K> + ?Sized, K: Hash + Eq, S: BuildHasher,
Access IndexMap
values corresponding to a key.
Examples
use indexmap::IndexMap;
let mut map = IndexMap::new();
for word in "Lorem ipsum dolor sit amet".split_whitespace() {
map.insert(word.to_lowercase(), word.to_uppercase());
}
assert_eq!(map["lorem"], "LOREM");
assert_eq!(map["ipsum"], "IPSUM");
use indexmap::IndexMap;
let mut map = IndexMap::new();
map.insert("foo", 1);
println!("{:?}", map["bar"]); // panics!
source§impl<K, V, S> Index<usize> for IndexMap<K, V, S>
impl<K, V, S> Index<usize> for IndexMap<K, V, S>
Access IndexMap
values at indexed positions.
Examples
use indexmap::IndexMap;
let mut map = IndexMap::new();
for word in "Lorem ipsum dolor sit amet".split_whitespace() {
map.insert(word.to_lowercase(), word.to_uppercase());
}
assert_eq!(map[0], "LOREM");
assert_eq!(map[1], "IPSUM");
map.reverse();
assert_eq!(map[0], "AMET");
assert_eq!(map[1], "SIT");
map.sort_keys();
assert_eq!(map[0], "AMET");
assert_eq!(map[1], "DOLOR");
use indexmap::IndexMap;
let mut map = IndexMap::new();
map.insert("foo", 1);
println!("{:?}", map[10]); // panics!
source§impl<N, E, Ty> Index<(N, N)> for GraphMap<N, E, Ty>where
N: NodeTrait,
Ty: EdgeType,
impl<N, E, Ty> Index<(N, N)> for GraphMap<N, E, Ty>where N: NodeTrait, Ty: EdgeType,
Index GraphMap
by node pairs to access edge weights.
source§impl<N, E, Ty, Ix> Index<EdgeIndex<Ix>> for StableGraph<N, E, Ty, Ix>where
Ty: EdgeType,
Ix: IndexType,
impl<N, E, Ty, Ix> Index<EdgeIndex<Ix>> for StableGraph<N, E, Ty, Ix>where Ty: EdgeType, Ix: IndexType,
Index the StableGraph
by EdgeIndex
to access edge weights.
Panics if the edge doesn’t exist.
source§impl<N, E, Ty, Ix> Index<EdgeIndex<Ix>> for Graph<N, E, Ty, Ix>where
Ty: EdgeType,
Ix: IndexType,
impl<N, E, Ty, Ix> Index<EdgeIndex<Ix>> for Graph<N, E, Ty, Ix>where Ty: EdgeType, Ix: IndexType,
Index the Graph
by EdgeIndex
to access edge weights.
Panics if the edge doesn’t exist.
source§impl<N, E, Ty, Ix> Index<NodeIndex<Ix>> for StableGraph<N, E, Ty, Ix>where
Ty: EdgeType,
Ix: IndexType,
impl<N, E, Ty, Ix> Index<NodeIndex<Ix>> for StableGraph<N, E, Ty, Ix>where Ty: EdgeType, Ix: IndexType,
Index the StableGraph
by NodeIndex
to access node weights.
Panics if the node doesn’t exist.
source§impl<N, E, Ty, Ix> Index<NodeIndex<Ix>> for Graph<N, E, Ty, Ix>where
Ty: EdgeType,
Ix: IndexType,
impl<N, E, Ty, Ix> Index<NodeIndex<Ix>> for Graph<N, E, Ty, Ix>where Ty: EdgeType, Ix: IndexType,
Index the Graph
by NodeIndex
to access node weights.
Panics if the node doesn’t exist.
source§impl<N, E, Ty, Null, Ix> Index<(NodeIndex<Ix>, NodeIndex<Ix>)> for MatrixGraph<N, E, Ty, Null, Ix>where
Ty: EdgeType,
Null: Nullable<Wrapped = E>,
Ix: IndexType,
impl<N, E, Ty, Null, Ix> Index<(NodeIndex<Ix>, NodeIndex<Ix>)> for MatrixGraph<N, E, Ty, Null, Ix>where Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType,
Index the MatrixGraph
by NodeIndex
pair to access edge weights.
Also available with indexing syntax: &graph[e]
.
Panics if no edge exists between a
and b
.
source§impl<N, E, Ty, Null, Ix> Index<NodeIndex<Ix>> for MatrixGraph<N, E, Ty, Null, Ix>where
Ty: EdgeType,
Null: Nullable<Wrapped = E>,
Ix: IndexType,
impl<N, E, Ty, Null, Ix> Index<NodeIndex<Ix>> for MatrixGraph<N, E, Ty, Null, Ix>where Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType,
Index the MatrixGraph
by NodeIndex
to access node weights.
Panics if the node doesn’t exist.
const: unstable · source§impl<T, I> Index<I> for [T]where
I: SliceIndex<[T]>,
impl<T, I> Index<I> for [T]where I: SliceIndex<[T]>,
type Output = <I as SliceIndex<[T]>>::Output
source§impl<T, I, A> Index<I> for Vec<T, A>where
I: SliceIndex<[T]>,
A: Allocator,
impl<T, I, A> Index<I> for Vec<T, A>where I: SliceIndex<[T]>, A: Allocator,
type Output = <I as SliceIndex<[T]>>::Output
1.50.0 (const: unstable) · source§impl<T, I, const N: usize> Index<I> for [T; N]where
[T]: Index<I>,
impl<T, I, const N: usize> Index<I> for [T; N]where [T]: Index<I>,
source§impl<T, S> Index<usize> for IndexSet<T, S>
impl<T, S> Index<usize> for IndexSet<T, S>
Access IndexSet
values at indexed positions.
Examples
use indexmap::IndexSet;
let mut set = IndexSet::new();
for word in "Lorem ipsum dolor sit amet".split_whitespace() {
set.insert(word.to_string());
}
assert_eq!(set[0], "Lorem");
assert_eq!(set[1], "ipsum");
set.reverse();
assert_eq!(set[0], "amet");
assert_eq!(set[1], "sit");
set.sort();
assert_eq!(set[0], "Lorem");
assert_eq!(set[1], "amet");
use indexmap::IndexSet;
let mut set = IndexSet::new();
set.insert("foo");
println!("{:?}", set[10]); // panics!