Trait Index

pub trait Index<Idx>
where
    Idx: ?Sized,
{
    type Output: ?Sized;

    // Required method
    fn index(&self, index: Idx) -> &Self::Output;
}

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

type Output: ?Sized

The returned type after indexing.

Required Methods

fn index(&self, index: Idx) -> &Self::Output

Performs the indexing (container[index]) operation.

Panics

May panic if the index is out of bounds.

Implementors

impl Index<usize> for ByteString

type Output = u8

impl Index<usize> for ByteRecord

type Output = [u8]

impl Index<usize> for StringRecord

type Output = str

impl Index<Range<Position>> for Url

type Output = str

impl Index<Range<usize>> for UninitSlice

type Output = UninitSlice

impl Index<Range<usize>> for ByteString

type Output = ByteStr

impl Index<RangeFrom<Position>> for Url

type Output = str

impl Index<RangeFrom<usize>> for UninitSlice

type Output = UninitSlice

impl Index<RangeFrom<usize>> for ByteString

type Output = ByteStr

impl Index<RangeFrom<usize>> for CStr

type Output = CStr

impl Index<RangeFull> for UninitSlice

type Output = UninitSlice

impl Index<RangeFull> for ByteString

type Output = ByteStr

impl Index<RangeFull> for CString

type Output = CStr

impl Index<RangeFull> for OsString

type Output = OsStr

impl Index<RangeFull> for Url

type Output = str

impl Index<RangeInclusive<usize>> for UninitSlice

type Output = UninitSlice

impl Index<RangeInclusive<usize>> for ByteString

type Output = ByteStr

impl Index<RangeTo<Position>> for Url

type Output = str

impl Index<RangeTo<usize>> for UninitSlice

type Output = UninitSlice

impl Index<RangeTo<usize>> for ByteString

type Output = ByteStr

impl Index<RangeToInclusive<usize>> for UninitSlice

type Output = UninitSlice

impl Index<RangeToInclusive<usize>> for ByteString

type Output = ByteStr

impl Index<Span> for str

type Output = str

impl Index<Span> for str

type Output = str

impl Index<Span> for [u8]

type Output = [u8]

impl Index<Span> for [u8]

type Output = [u8]

impl<'a> Index<usize> for BerObject<'a>

type Output = BerObject<'a>

impl<'a> Index<usize> for InputPair<'a>

type Output = u8

impl<'a, T> Index<usize> for AllocatedStackMemory<'a, T>

type Output = T

impl<'a, T> Index<usize> for HeapPrealloc<'a, T>

where T: 'a,

type Output = [T]

impl<'a, T> Index<Range<usize>> for AllocatedStackMemory<'a, T>

type Output = [T]

impl<'h> Index<usize> for rama::http::matcher::uri::dep::regex::bytes::Captures<'h>

Get a matching capture group’s haystack substring by index.

The haystack substring returned can’t outlive the Captures object if this method is used, because of how Index is defined (normally a[i] is part of a and can’t outlive it). To work around this limitation, do that, use Captures::get instead.

'h is the lifetime of the matched haystack, but the lifetime of the &str returned by this implementation is the lifetime of the Captures value itself.

Panics

If there is no matching group at the given index.

type Output = [u8]

impl<'h> Index<usize> for rama::http::matcher::uri::dep::regex::Captures<'h>

Get a matching capture group’s haystack substring by index.

The haystack substring returned can’t outlive the Captures object if this method is used, because of how Index is defined (normally a[i] is part of a and can’t outlive it). To work around this limitation, do that, use Captures::get instead.

'h is the lifetime of the matched haystack, but the lifetime of the &str returned by this implementation is the lifetime of the Captures value itself.

Panics

If there is no matching group at the given index.

type Output = str

impl<'h, 'n> Index<&'n str> for rama::http::matcher::uri::dep::regex::bytes::Captures<'h>

Get a matching capture group’s haystack substring by name.

The haystack substring returned can’t outlive the Captures object if this method is used, because of how Index is defined (normally a[i] is part of a and can’t outlive it). To work around this limitation, do that, use Captures::name instead.

'h is the lifetime of the matched haystack, but the lifetime of the &str returned by this implementation is the lifetime of the Captures value itself.

'n is the lifetime of the group name used to index the Captures value.

Panics

If there is no matching group at the given name.

type Output = [u8]

impl<'h, 'n> Index<&'n str> for rama::http::matcher::uri::dep::regex::Captures<'h>

Get a matching capture group’s haystack substring by name.

The haystack substring returned can’t outlive the Captures object if this method is used, because of how Index is defined (normally a[i] is part of a and can’t outlive it). To work around this limitation, do that, use Captures::name instead.

'h is the lifetime of the matched haystack, but the lifetime of the &str returned by this implementation is the lifetime of the Captures value itself.

'n is the lifetime of the group name used to index the Captures value.

Panics

If there is no matching group at the given name.

type Output = str

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]>,

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]>,

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]>,

type Output = <I as SliceIndex<[<A as Array>::Item]>>::Output

impl<AllocU32> Index<BucketPopIndex> for EntropyBucketPopulation<AllocU32>

where AllocU32: Allocator<u32>,

type Output = u32

impl<I> Index<I> for Value

where I: Index,

type Output = Value

impl<I> Index<I> for str

where I: SliceIndex<str>,

type Output = <I as SliceIndex<str>>::Output

impl<I> Index<I> for String

where I: SliceIndex<str>,

type Output = <I as SliceIndex<str>>::Output

impl<I> Index<I> for ByteStr

where I: SliceIndex<ByteStr>,

type Output = <I as SliceIndex<ByteStr>>::Output

impl<I, T, const N: usize> Index<I> for Simd<T, N>

where T: SimdElement, LaneCount<N>: SupportedLaneCount, I: SliceIndex<[T]>,

type Output = <I as SliceIndex<[T]>>::Output

impl<K, Q, V, A> Index<&Q> for BTreeMap<K, V, A>

where A: Allocator + Clone, K: Borrow<Q> + Ord, Q: Ord + ?Sized,

type Output = V

impl<K, Q, V, S> Index<&Q> for rama::crypto::dep::x509_parser::prelude::asn1_rs::nom::lib::std::collections::HashMap<K, V, S>

where K: Eq + Hash + Borrow<Q>, Q: Eq + Hash + ?Sized, S: BuildHasher,

type Output = V

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,

type Output = V

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,

type Output = V

impl<K, T> Index<K> for HeaderMap<T>

where K: AsHeaderName,

type Output = T

impl<K, V> Index<(Bound<usize>, Bound<usize>)> for Slice<K, V>

type Output = Slice<K, V>

impl<K, V> Index<usize> for Keys<'_, K, V>

Access [IndexMap] keys at indexed positions.

While Index<usize> for IndexMap accesses a map’s values, indexing through [IndexMap::keys] offers an alternative to access a map’s keys instead.

Since Keys is also an iterator, consuming items from the iterator will offset the effective indices. Similarly, if Keys is obtained from [Slice::keys], indices will be interpreted relative to the position of that slice.

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.keys()[0], "lorem");
assert_eq!(map[1], "IPSUM");
assert_eq!(map.keys()[1], "ipsum");

map.reverse();
assert_eq!(map.keys()[0], "amet");
assert_eq!(map.keys()[1], "sit");

map.sort_keys();
assert_eq!(map.keys()[0], "amet");
assert_eq!(map.keys()[1], "dolor");

// Advancing the iterator will offset the indexing
let mut keys = map.keys();
assert_eq!(keys[0], "amet");
assert_eq!(keys.next().map(|s| &**s), Some("amet"));
assert_eq!(keys[0], "dolor");
assert_eq!(keys[1], "ipsum");

// Slices may have an offset as well
let slice = &map[2..];
assert_eq!(slice[0], "IPSUM");
assert_eq!(slice.keys()[0], "ipsum");

use indexmap::IndexMap;

let mut map = IndexMap::new();
map.insert("foo", 1);
println!("{:?}", map.keys()[10]); // panics!

type Output = K

impl<K, V> Index<usize> for Slice<K, V>

type Output = V

impl<K, V> Index<Range<usize>> for Slice<K, V>

type Output = Slice<K, V>

impl<K, V> Index<RangeFrom<usize>> for Slice<K, V>

type Output = Slice<K, V>

impl<K, V> Index<RangeFull> for Slice<K, V>

type Output = Slice<K, V>

impl<K, V> Index<RangeInclusive<usize>> for Slice<K, V>

type Output = Slice<K, V>

impl<K, V> Index<RangeTo<usize>> for Slice<K, V>

type Output = Slice<K, V>

impl<K, V> Index<RangeToInclusive<usize>> for Slice<K, V>

type Output = Slice<K, V>

impl<K, V, Q, S> Index<&Q> for IndexMap<K, V, S>

where Q: Hash + Equivalent<K> + ?Sized, 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!

type Output = V

impl<K, V, S> Index<(Bound<usize>, Bound<usize>)> for IndexMap<K, V, S>

type Output = Slice<K, V>

impl<K, V, S> Index<&K> for LiteMap<K, V, S>

where K: Ord, S: Store<K, V>,

type Output = V

impl<K, V, S> Index<usize> for IndexMap<K, V, S>

Access [IndexMap] values at indexed positions.

See Index<usize> for Keys to access a map’s keys instead.

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!

type Output = V

impl<K, V, S> Index<Range<usize>> for IndexMap<K, V, S>

type Output = Slice<K, V>

impl<K, V, S> Index<RangeFrom<usize>> for IndexMap<K, V, S>

type Output = Slice<K, V>

impl<K, V, S> Index<RangeFull> for IndexMap<K, V, S>

type Output = Slice<K, V>

impl<K, V, S> Index<RangeInclusive<usize>> for IndexMap<K, V, S>

type Output = Slice<K, V>

impl<K, V, S> Index<RangeTo<usize>> for IndexMap<K, V, S>

type Output = Slice<K, V>

impl<K, V, S> Index<RangeToInclusive<usize>> for IndexMap<K, V, S>

type Output = Slice<K, V>

impl<Q> Index<&Q> for Map<String, Value>

where String: Borrow<Q>, Q: Ord + Eq + Hash + ?Sized,

Access an element of this map. Panics if the given key is not present in the map.

match val {
    Value::String(s) => Some(s.as_str()),
    Value::Array(arr) => arr[0].as_str(),
    Value::Object(map) => map["type"].as_str(),
    _ => None,
}

type Output = Value

impl<T> Index<(Bound<usize>, Bound<usize>)> for Slice<T>

type Output = Slice<T>

impl<T> Index<usize> for StackRef<T>

where T: Stackable,

type Output = <T as ForeignType>::Ref

impl<T> Index<usize> for Slab<T>

type Output = T

impl<T> Index<usize> for Slice<T>

type Output = T

impl<T> Index<usize> for WrapBox<T>

type Output = T

impl<T> Index<Range<usize>> for Slice<T>

type Output = Slice<T>

impl<T> Index<Range<usize>> for WrapBox<T>

type Output = [T]

impl<T> Index<RangeFrom<usize>> for Slice<T>

type Output = Slice<T>

impl<T> Index<RangeFull> for Slice<T>

type Output = Slice<T>

impl<T> Index<RangeInclusive<usize>> for Slice<T>

type Output = Slice<T>

impl<T> Index<RangeTo<usize>> for Slice<T>

type Output = Slice<T>

impl<T> Index<RangeToInclusive<usize>> for Slice<T>

type Output = Slice<T>

impl<T> Index<PatternID> for [T]

type Output = T

impl<T> Index<PatternID> for [T]

type Output = T

impl<T> Index<PatternID> for rama::crypto::dep::x509_parser::prelude::asn1_rs::nom::lib::std::vec::Vec<T>

type Output = T

impl<T> Index<PatternID> for rama::crypto::dep::x509_parser::prelude::asn1_rs::nom::lib::std::vec::Vec<T>

type Output = T

impl<T> Index<SmallIndex> for [T]

type Output = T

impl<T> Index<SmallIndex> for [T]

type Output = T

impl<T> Index<SmallIndex> for rama::crypto::dep::x509_parser::prelude::asn1_rs::nom::lib::std::vec::Vec<T>

type Output = T

impl<T> Index<SmallIndex> for rama::crypto::dep::x509_parser::prelude::asn1_rs::nom::lib::std::vec::Vec<T>

type Output = T

impl<T> Index<StateID> for [T]

type Output = T

impl<T> Index<StateID> for [T]

type Output = T

impl<T> Index<StateID> for rama::crypto::dep::x509_parser::prelude::asn1_rs::nom::lib::std::vec::Vec<T>

type Output = T

impl<T> Index<StateID> for rama::crypto::dep::x509_parser::prelude::asn1_rs::nom::lib::std::vec::Vec<T>

type Output = T

impl<T, A> Index<usize> for VecDeque<T, A>

where A: Allocator,

type Output = T

impl<T, F> Index<usize> for VarZeroSlice<T, F>

where T: VarULE + ?Sized, F: VarZeroVecFormat,

type Output = T

impl<T, I> Index<I> for [T]

where I: SliceIndex<[T]>,

type Output = <I as SliceIndex<[T]>>::Output

impl<T, I, A> Index<I> for rama::crypto::dep::x509_parser::prelude::asn1_rs::nom::lib::std::vec::Vec<T, A>

where I: SliceIndex<[T]>, A: Allocator,

type Output = <I as SliceIndex<[T]>>::Output

impl<T, I, A> Index<I> for Vec<T, A>

where I: SliceIndex<[T]>, A: Allocator,

type Output = <I as SliceIndex<[T]>>::Output

impl<T, I, const N: usize> Index<I> for [T; N]

where [T]: Index<I>,

type Output = <[T] as Index<I>>::Output

impl<T, S> Index<(Bound<usize>, Bound<usize>)> for IndexSet<T, S>

type Output = Slice<T>

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!

type Output = T

impl<T, S> Index<Range<usize>> for IndexSet<T, S>

type Output = Slice<T>

impl<T, S> Index<RangeFrom<usize>> for IndexSet<T, S>

type Output = Slice<T>

impl<T, S> Index<RangeFull> for IndexSet<T, S>

type Output = Slice<T>

impl<T, S> Index<RangeInclusive<usize>> for IndexSet<T, S>

type Output = Slice<T>

impl<T, S> Index<RangeTo<usize>> for IndexSet<T, S>

type Output = Slice<T>

impl<T, S> Index<RangeToInclusive<usize>> for IndexSet<T, S>

type Output = Slice<T>