### Example Searches for Rs Slotmap

Source: https://docs.rs/slotmap/latest/src/slotmap/secondary.rs_search=

Provides example search queries for common Rust patterns within the Rs Slotmap project. These examples demonstrate how to search for standard library types, type conversions, and generic function signatures.

```text
Example searches:
  * std::vec
  * u32 -> bool
  * Option<T>, (T -> U) -> Option<U>
```

--------------------------------

### SlotMap and SecondaryMap Initialization and Entry Operations (Rust)

Source: https://docs.rs/slotmap/latest/slotmap/secondary/struct.OccupiedEntry

Demonstrates the initialization of SlotMap and SecondaryMap, and showcases various operations on an occupied entry using the slotmap crate. This includes getting the key, removing the entry, getting a reference to the value, getting a mutable reference, converting to a mutable reference, inserting a new value, and removing the value.

```Rust
let mut sm = SlotMap::new();
let mut sec = SecondaryMap::new();

let k = sm.insert(1);
sec.insert(k, 10);
assert_eq!(sec.entry(k).unwrap().key(), k);

if let Some(Entry::Occupied(o)) = sec.entry(k) {
    assert_eq!(o.remove_entry(), (k, 10));
}
assert_eq!(sec.contains_key(k), false);

let k = sm.insert(1);
sec.insert(k, 10);

if let Entry::Occupied(o) = sec.entry(k).unwrap() {
    assert_eq!(*o.get(), 10);
}

let mut sm = SlotMap::new();
let mut sec = SecondaryMap::new();

let k = sm.insert(1);
sec.insert(k, 10);
if let Entry::Occupied(mut o) = sec.entry(k).unwrap() {
    *o.get_mut() = 20;
}
assert_eq!(sec[k], 20);

let mut sm = SlotMap::new();
let mut sec = SecondaryMap::new();

let k = sm.insert(0);
sec.insert(k, 0);

let r;
if let Entry::Occupied(o) = sec.entry(k).unwrap() {
    r = o.into_mut(); // v outlives the entry.
} else {
    r = sm.get_mut(k).unwrap();
}
*r = 1;
assert_eq!((sm[k], sec[k]), (0, 1));

let mut sm = SlotMap::new();
let mut sec = SecondaryMap::new();

let k = sm.insert(1);
sec.insert(k, 10);

if let Entry::Occupied(mut o) = sec.entry(k).unwrap() {
    let v = o.insert(20);
    assert_eq!(v, 10);
    assert_eq!(*o.get(), 20);
}

let mut sm = SlotMap::new();
let mut sec = SecondaryMap::new();

let k = sm.insert(1);
sec.insert(k, 10);

if let Entry::Occupied(mut o) = sec.entry(k).unwrap() {
    assert_eq!(o.remove(), 10);
    assert_eq!(sec.contains_key(k), false);
}

```

--------------------------------

### Utility Functions

Source: https://docs.rs/slotmap/latest/src/slotmap/util.rs_search=u32+-%3E+bool

Utility functions provided by the slotmap crate.

```APIDOC
## Utility Functions

### `is_older_version(a: u32, b: u32) -> bool`

#### Description
Returns if `a` is an older version than `b`, taking into account wrapping of versions.

#### Method
GET

#### Endpoint
`/slotmap/util/is_older_version`

#### Query Parameters
- **a** (u32) - Required - The first version to compare.
- **b** (u32) - Required - The second version to compare.

#### Request Example
```json
{
  "example": "No request body needed for this GET request."
}
```

#### Response
##### Success Response (200)
- **bool** (boolean) - `true` if `a` is older than `b`, `false` otherwise.

#### Response Example
```json
{
  "example": true
}
```

### `Never` Enum

#### Description
Internal stable replacement for `!`. Used to indicate a value that can never occur.

#### Methods
- `unwrap_never(self) -> T`
  - Description: Unwraps the `Result<T, Never>` into `T`. This method will panic if the `Err` variant is encountered, as `Never` cannot be constructed.
  - Method: GET
  - Endpoint: `/slotmap/util/Never/unwrap_never`
  - Request Example: `"example": "No request body needed for this GET request."`
  - Response Example: `"example": "The unwrapped value T."`

### `PanicOnDrop` Struct

#### Description
A struct that panics when dropped, used for debugging purposes.

#### Fields
- **0** (&'static str) - The panic message to be displayed when the struct is dropped.

#### Method
DROP (Implicit)

#### Example Usage (Conceptual)
```rust
let _panic_on_drop = PanicOnDrop("This should not be dropped!");
// When the scope ends, the struct is dropped and panics.
```
```

--------------------------------

### Construct SparseSecondaryMap with Custom Hasher

Source: https://docs.rs/slotmap/latest/slotmap/sparse_secondary/struct.SparseSecondaryMap_search=

Illustrates how to initialize a SparseSecondaryMap using a specific hash builder. This allows for control over the hashing algorithm used for keys.

```rust
let mut sm: SlotMap<_, i32> = SlotMap::with_capacity(10);
let mut sec: SparseSecondaryMap<DefaultKey, i32, _> =
    SparseSecondaryMap::with_hasher(RandomState::new());
```

--------------------------------

### Get Mutable Values from SlotMap

Source: https://docs.rs/slotmap/latest/slotmap/dense/struct.DenseSlotMap_search=

Demonstrates how to get an iterator over mutable references to all values in a SlotMap using `values_mut`. This allows modifying all values, for example, by applying a transformation.

```rust
use std::collections::HashSet;

let mut sm = DenseSlotMap::new();
sm.insert(1);
sm.insert(2);
sm.insert(3);
sm.values_mut().for_each(|n| { *n *= 3 });
let values: HashSet<_> = sm.into_iter().map(|(_k, v)| v).collect();
let check: HashSet<_> = vec![3, 6, 9].into_iter().collect();
assert_eq!(values, check);
```

--------------------------------

### Get Immutable Reference to Value - Rust Example

Source: https://docs.rs/slotmap/latest/slotmap/sparse_secondary/struct.OccupiedEntry_search=

Illustrates how to obtain an immutable reference to the value within an `OccupiedEntry` using the `get()` method. This allows inspecting the value without modifying it.

```rust
let mut sm = SlotMap::new();
let mut sec = SparseSecondaryMap::new();

let k = sm.insert(1);
sec.insert(k, 10);

if let Entry::Occupied(o) = sec.entry(k).unwrap() {
    assert_eq!(*o.get(), 10);
}
```

--------------------------------

### SlotMap Basic Usage Example

Source: https://docs.rs/slotmap/latest/src/slotmap/lib.rs

Demonstrates the basic usage of SlotMap, including inserting elements, accessing them by key, removing elements, and reusing space. It also shows the creation and usage of a SecondaryMap.

```rust
#![doc(html_root_url = "https://docs.rs/slotmap/1.1.1")]
#![crate_name = "slotmap"]
#![cfg_attr(all(not(test), not(feature = "std")), no_std)]
#![cfg_attr(all(nightly, doc), feature(doc_cfg))]
#![warn(
    missing_debug_implementations,
    trivial_casts,
    trivial_numeric_casts,
    unused_lifetimes,
    unused_import_braces
)]
#![deny(missing_docs)]
#![deny(clippy::all)]
#![allow(
    clippy::while_let_on_iterator, // Style differences.
    clippy::unnecessary_map_or // Too high MSRV.
)]

//! # slotmap
//! 
//! This library provides a container with persistent unique keys to access
//! stored values, [`SlotMap`]. Upon insertion a key is returned that can be
//! used to later access or remove the values. Insertion, removal and access all
//! take O(1) time with low overhead. Great for storing collections of objects
//! that need stable, safe references but have no clear ownership otherwise, 
//! such as game entities or graph nodes.
//! 
//! The difference between a [`BTreeMap`] or [`HashMap`] and a slot map is
//! that the slot map generates and returns the key when inserting a value. A
//! key is always unique and will only refer to the value that was inserted.
//! A slot map's main purpose is to simply own things in a safe and efficient
//! manner.
//! 
//! You can also create (multiple) secondary maps that can map the keys returned
//! by [`SlotMap`] to other values, to associate arbitrary data with objects
//! stored in slot maps, without hashing required - it's direct indexing under
//! the hood.
//! 
//! The minimum required stable Rust version for this crate is 1.58.
//! 
//! # Examples
//! 
//! ```
//! # use slotmap::*; 
//! let mut sm = SlotMap::new();
//! let foo = sm.insert("foo");  // Key generated on insert.
//! let bar = sm.insert("bar");
//! assert_eq!(sm[foo], "foo");
//! assert_eq!(sm[bar], "bar");
//! 
//! sm.remove(bar);
//! let reuse = sm.insert("reuse");  // Space from bar reused.
//! assert_eq!(sm.contains_key(bar), false);  // After deletion a key stays invalid.
//! 
//! let mut sec = SecondaryMap::new();
//! sec.insert(foo, "noun");  // We provide the key for secondary maps.
//! sec.insert(reuse, "verb");
//! 
//! for (key, val) in sm {
//!     println!("{} is a {}", val, sec[key]);
//! }
//! ```
//! 
//! # Serialization through [`serde`], [`no_std`] support and unstable features
//! 
//! Both keys and the slot maps have full (de)seralization support through
//! the [`serde`] library. A key remains valid for a slot map even after one or
//! both have been serialized and deserialized! This makes storing or
//! transferring complicated referential structures and graphs a breeze. Care has
//! been taken such that deserializing keys and slot maps from untrusted sources
//! is safe. If you wish to use these features you must enable the `serde`
//! feature flag for `slotmap` in your `Cargo.toml`.
//! 
//! ```text
//! slotmap = { version = "1.0", features = ["serde"] }
//! ```
//! 
//! This crate also supports [`no_std`] environments, but does require the
//! [`alloc`] crate to be available. To enable this you have to disable the
//! `std` feature that is enabled by default:
//! 
//! ```text
//! slotmap = { version = "1.0", default-features = false }
//! ```
//! 
//! Unfortunately [`SparseSecondaryMap`] is not available in [`no_std`], because
//! it relies on [`HashMap`]. Finally the `unstable` feature can be defined to
//! enable the parts of `slotmap` that only work on nightly Rust.
//! 
//! # Why not index a [`Vec`], or use [`slab`], [`stable-vec`], etc?
//! 
//! Those solutions either can not reclaim memory from deleted elements or
//! suffer from the ABA problem. The keys returned by `slotmap` are versioned.
//! This means that once a key is removed, it stays removed, even if the
//! physical storage inside the slotmap is reused for new elements. The key is a
//! permanently unique<sup>*</sup> reference to the inserted value. Despite
//! supporting versioning, a [`SlotMap`] is often not (much) slower than the
//! alternative, by internally using carefully checked unsafe code. Finally,
//! `slotmap` simply has a lot of features that make your life easy.
//! 
//! # Performance characteristics and implementation details
//! 
//! Insertion, access and deletion is all O(1) with low overhead by storing the
//! elements inside a [`Vec`]. Unlike references or indices into a vector, 
//! unless you remove a key it is never invalidated. Behind the scenes each
//! slot in the vector is a `(value, version)` tuple. After insertion the
//! returned key also contains a version. Only when the stored version and
//! version in a key match is a key valid.

```

--------------------------------

### Get Value by Key in HopSlotMap

Source: https://docs.rs/slotmap/latest/slotmap/hop/struct.HopSlotMap

Shows how to retrieve a reference to a value associated with a key in a HopSlotMap using the `get` method. It returns `Some(&V)` if the key exists and `None` otherwise. The example also demonstrates that accessing a removed key results in `None`.

```rust
let mut sm = HopSlotMap::new();
let key = sm.insert("bar");
assert_eq!(sm.get(key), Some(&"bar"));
sm.remove(key);
assert_eq!(sm.get(key), None);
```

--------------------------------

### Get Key from VacantEntry - Rust Example

Source: https://docs.rs/slotmap/latest/slotmap/secondary/struct.VacantEntry_search=

Demonstrates how to retrieve the key associated with a VacantEntry. This is useful when you need to know the key before inserting a value into the SecondaryMap.

```rust
let mut sm = SlotMap::new();
let mut sec: SecondaryMap<_, ()> = SecondaryMap::new();

let k = sm.insert(1);

if let Entry::Vacant(v) = sec.entry(k).unwrap() {
    assert_eq!(v.key(), k);
}
```

--------------------------------

### SlotMap Initialization with Capacity and Custom Key Type

Source: https://docs.rs/slotmap/latest/slotmap/basic/struct.SlotMap

Demonstrates initializing a SlotMap with both a specified capacity and a custom key type. This combines pre-allocation benefits with custom key management.

```rust
new_key_type! {
    struct MessageKey;
}
let mut messages = SlotMap::with_capacity_and_key(3);
let welcome: MessageKey = messages.insert("Welcome");
let good_day = messages.insert("Good day");
let hello = messages.insert("Hello");
```

--------------------------------

### Get Key from VacantEntry in Rust

Source: https://docs.rs/slotmap/latest/slotmap/sparse_secondary/struct.VacantEntry_search=std%3A%3Avec

Retrieves the key that would be used for inserting a value into a SparseSecondaryMap via a VacantEntry. This is demonstrated with an example showing its usage with SlotMap.

```rust
pub fn key(&self) -> K
```

```rust
let mut sm = SlotMap::new();
let mut sec: SparseSecondaryMap<_, ()> = SparseSecondaryMap::new();

let k = sm.insert(1);

if let Entry::Vacant(v) = sec.entry(k).unwrap() {
    assert_eq!(v.key(), k);
}
```

--------------------------------

### SecondaryMap Initialization and Usage Example (Rust)

Source: https://docs.rs/slotmap/latest/slotmap/secondary/struct.SecondaryMap

Demonstrates how to initialize a SecondaryMap and associate data with keys from a SlotMap. It shows inserting elements into both maps, populating the SecondaryMap, and accessing/modifying associated data.

```rust
let mut players = SlotMap::new();
let mut health = SecondaryMap::new();
let mut ammo = SecondaryMap::new();

let alice = players.insert("alice");
let bob = players.insert("bob");

for p in players.keys() {
    health.insert(p, 100);
    ammo.insert(p, 30);
}

// Alice attacks Bob with all her ammo!
health[bob] -= ammo[alice] * 3;
ammo[alice] = 0;
```

--------------------------------

### Get Mutable Reference to Value - Rust Example

Source: https://docs.rs/slotmap/latest/slotmap/sparse_secondary/struct.OccupiedEntry_search=

Demonstrates obtaining a mutable reference to the value within an `OccupiedEntry` using `get_mut()`. This allows in-place modification of the entry's value.

```rust
let mut sm = SlotMap::new();
let mut sec = SparseSecondaryMap::new();

let k = sm.insert(1);
sec.insert(k, 10);
if let Entry::Occupied(mut o) = sec.entry(k).unwrap() {
    *o.get_mut() = 20;
}
assert_eq!(sec[k], 20);
```

--------------------------------

### Construct SparseSecondaryMap with Default Hasher

Source: https://docs.rs/slotmap/latest/slotmap/sparse_secondary/struct.SparseSecondaryMap_search=

Shows how to create a new, empty SparseSecondaryMap using the default RandomState hasher. This is the simplest way to initialize the map.

```rust
let mut sec: SparseSecondaryMap<DefaultKey, i32> = SparseSecondaryMap::new();
```

--------------------------------

### Getting KeyData from a Key (Rust)

Source: https://docs.rs/slotmap/latest/slotmap/trait.Key

Demonstrates how to retrieve the underlying `KeyData` from a key type that implements the `Key` trait. This example uses a custom key type `MyKey` and compares its `KeyData` with that of `DefaultKey`.

```rust
new_key_type! { struct MyKey; }
let dk = DefaultKey::null();
let mk = MyKey::null();
assert_eq!(dk.data(), mk.data());
```

--------------------------------

### Partitioning and Folding

Source: https://docs.rs/slotmap/latest/slotmap/dense/struct.Values

Adapters for partitioning elements and accumulating results.

```APIDOC
## partition<B, F>(self, f: F)

### Description
Consumes an iterator, creating two collections from it based on a predicate.

### Method
`partition`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```rust
// Example usage (conceptual)
let data = vec![1, 2, 3, 4, 5];
let (even, odd): (Vec<_>, Vec<_>) = data.into_iter().partition(|&x| x % 2 == 0);
```

### Response
#### Success Response (200)
A tuple containing two collections, partitioned according to the predicate.

#### Response Example
```rust
// Conceptual output
// (vec![2, 4], vec![1, 3, 5])
```

## is_partitioned<P>(self, predicate: P)

### Description
Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return `true` precede all those that return `false`.

### Method
`is_partitioned`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```rust
// Example usage (conceptual)
// Note: This is a nightly-only experimental API.
// let data = vec![2, 4, 1, 3, 5];
// let is_part = data.into_iter().is_partitioned(|&x| x % 2 == 0);
```

### Response
#### Success Response (200)
A boolean indicating whether the iterator is partitioned.

#### Response Example
```rust
// Conceptual output
// true (if partitioned correctly)
```

## try_fold<B, F, R>(&mut self, init: B, f: F)

### Description
An iterator method that applies a function as long as it returns successfully, producing a single, final value.

### Method
`try_fold`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```rust
// Example usage (conceptual)
let mut data = vec![1, 2, 3];
let result = data.iter().try_fold(0, |acc, &x| {
    if x < 5 { Ok(acc + x) } else { Err("Too large") }
});
```

### Response
#### Success Response (200)
The final accumulated value if the operation succeeds for all elements, or the first error encountered.

#### Response Example
```rust
// Conceptual output
// Result<i32, &str> containing Ok(6) or Err("Too large")
```

## try_for_each<F, R>(&mut self, f: F)

### Description
An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error.

### Method
`try_for_each`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```rust
// Example usage (conceptual)
let mut data = vec![1, 2, 3];
let result = data.iter().try_for_each(|&x| {
    if x < 5 { println!("Processing: {}", x); Ok(()) } else { Err("Too large") }
});
```

### Response
#### Success Response (200)
`Ok(())` if the function succeeds for all elements, or the first error encountered.

#### Response Example
```rust
// Conceptual output
// Result<(), &str> containing Ok(()) or Err("Too large")
```

## fold<B, F>(self, init: B, f: F)

### Description
Folds every element into an accumulator by applying an operation, returning the final result.

### Method
`fold`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```rust
// Example usage (conceptual)
let data = vec![1, 2, 3];
let sum: i32 = data.iter().fold(0, |acc, &x| acc + x);
```

### Response
#### Success Response (200)
The final accumulated value.

#### Response Example
```rust
// Conceptual output
// 6
```

## reduce<F>(self, f: F)

### Description
Reduces the elements to a single one by repeatedly applying a reducing operation.

### Method
`reduce`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```rust
// Example usage (conceptual)
let data = vec![1, 2, 3, 4, 5];
let product = data.iter().cloned().reduce(|acc, x| acc * x);
```

### Response
#### Success Response (200)
An `Option` containing the single reduced value, or `None` if the iterator was empty.

#### Response Example
```rust
// Conceptual output
// Some(120)
```
```

--------------------------------

### Construct SparseSecondaryMap with Capacity

Source: https://docs.rs/slotmap/latest/slotmap/sparse_secondary/struct.SparseSecondaryMap_search=

Demonstrates creating an empty SparseSecondaryMap with a specified initial capacity. This can help optimize performance by pre-allocating memory.

```rust
let mut sm: SlotMap<_, i32> = SlotMap::with_capacity(10);
let mut sec: SparseSecondaryMap<DefaultKey, i32> =
    SparseSecondaryMap::with_capacity(sm.capacity());
```

--------------------------------

### Get Mutable Value by Key in HopSlotMap

Source: https://docs.rs/slotmap/latest/slotmap/hop/struct.HopSlotMap

Illustrates how to obtain a mutable reference to a value in a HopSlotMap using the `get_mut` method. This allows in-place modification of the value. The example shows incrementing a floating-point value.

```rust
let mut sm = HopSlotMap::new();
let key = sm.insert(3.5);
if let Some(x) = sm.get_mut(key) {
    *x += 3.0;
}
assert_eq!(sm[key], 6.5);
```

--------------------------------

### Construct SparseSecondaryMap with Capacity and Custom Hasher

Source: https://docs.rs/slotmap/latest/slotmap/sparse_secondary/struct.SparseSecondaryMap_search=

Shows the creation of a SparseSecondaryMap with both a specified capacity and a custom hash builder. This provides fine-grained control over initialization.

```rust
let mut sm: SlotMap<_, i32> = SlotMap::with_capacity(10);
let mut sec: SparseSecondaryMap<DefaultKey, i32, _> =
    SparseSecondaryMap::with_capacity_and_hasher(10, RandomState::new());
```

--------------------------------

### Get Key from OccupiedEntry in SlotMap (Rust)

Source: https://docs.rs/slotmap/latest/src/slotmap/sparse_secondary.rs_search=

The `key` method for `OccupiedEntry` in `SlotMap` returns the key associated with the occupied entry. This is useful when you have an `OccupiedEntry` and need to retrieve its corresponding key, for example, for further lookups or operations.

```rust
impl<'a, K: Key, V> OccupiedEntry<'a, K, V> {
    /// Returns this entry's key.
    pub fn key(&self) -> K {
        self.kd.into()
    }
}
```

--------------------------------

### DenseSlotMap Initialization (Rust)

Source: https://docs.rs/slotmap/latest/slotmap/dense/struct.DenseSlotMap

Demonstrates how to create a new, empty DenseSlotMap using default keys or with a specified capacity. These methods are fundamental for starting to use the DenseSlotMap.

```Rust
use slotmap::DenseSlotMap;

// Create a new, empty DenseSlotMap with default keys
let mut sm: DenseSlotMap<_, i32> = DenseSlotMap::new();

// Create an empty DenseSlotMap with a specific capacity
let mut sm_with_capacity: DenseSlotMap<_, i32> = DenseSlotMap::with_capacity(10);

```

--------------------------------

### SlotMap Entry Manipulation with SecondaryMap (Rust)

Source: https://docs.rs/slotmap/latest/slotmap/secondary/struct.SecondaryMap

Shows how to use the `entry` method on a SecondaryMap to get an entry associated with a key from a SlotMap. If the entry doesn't exist, it inserts a default value. This example verifies that the inserted value is correct.

```rust
let mut sm = SlotMap::new();
let mut sec = SecondaryMap::new();
let k = sm.insert(1);
let v = sec.entry(k).unwrap().or_insert(10);
assert_eq!(*v, 10);
```

--------------------------------

### SparseSecondaryMap Constructors

Source: https://docs.rs/slotmap/latest/slotmap/sparse_secondary/struct.SparseSecondaryMap_search=

Documentation for the constructor methods of SparseSecondaryMap.

```APIDOC
## Constructors

### `SparseSecondaryMap::new()`

Constructs a new, empty `SparseSecondaryMap`.

#### Method

`pub fn new() -> Self`

#### Example

```rust
use slotmap::SparseSecondaryMap;
let mut sec: SparseSecondaryMap<slotmap::DefaultKey, i32> = SparseSecondaryMap::new();
```

### `SparseSecondaryMap::with_capacity(capacity: usize)`

Creates an empty `SparseSecondaryMap` with the given capacity of slots.

#### Method

`pub fn with_capacity(capacity: usize) -> Self`

#### Parameters

- **capacity** (`usize`) - The initial capacity of the secondary map.

#### Example

```rust
use slotmap::{SlotMap, SparseSecondaryMap};
let mut sm: SlotMap<_, i32> = SlotMap::with_capacity(10);
let mut sec: SparseSecondaryMap<slotmap::DefaultKey, i32> = SparseSecondaryMap::with_capacity(sm.capacity());
```

### `SparseSecondaryMap::with_hasher(hash_builder: S)`

Creates an empty `SparseSecondaryMap` which will use the given hash builder to hash keys.

#### Method

`pub fn with_hasher<S: BuildHasher>(hash_builder: S) -> Self`

#### Parameters

- **hash_builder** (`S`) - The `BuildHasher` to use for hashing keys.

#### Example

```rust
use slotmap::{SlotMap, SparseSecondaryMap};
use std::collections::hash_map::RandomState;

let mut sm: SlotMap<_, i32> = SlotMap::with_capacity(10);
let mut sec: SparseSecondaryMap<slotmap::DefaultKey, i32, _> = SparseSecondaryMap::with_hasher(RandomState::new());
```

### `SparseSecondaryMap::with_capacity_and_hasher(capacity: usize, hash_builder: S)`

Creates an empty `SparseSecondaryMap` with the given capacity of slots, using `hash_builder` to hash the keys.

#### Method

`pub fn with_capacity_and_hasher<S: BuildHasher>(capacity: usize, hash_builder: S) -> Self`

#### Parameters

- **capacity** (`usize`) - The initial capacity of the secondary map.
- **hash_builder** (`S`) - The `BuildHasher` to use for hashing keys.

#### Example

```rust
use slotmap::{SlotMap, SparseSecondaryMap};
use std::collections::hash_map::RandomState;

let mut sm: SlotMap<_, i32> = SlotMap::with_capacity(10);
let mut sec: SparseSecondaryMap<slotmap::DefaultKey, i32, _> = SparseSecondaryMap::with_capacity_and_hasher(10, RandomState::new());
```
```

--------------------------------

### Get Disjoint Mutable References (Unchecked) in Rust

Source: https://docs.rs/slotmap/latest/slotmap/secondary/struct.SecondaryMap

This function retrieves mutable references to values corresponding to given keys, assuming they are valid and disjoint. It is unsafe and should only be used if the keys are valid and unique. The example demonstrates how to use the function to swap values.

```Rust
let mut sm = SlotMap::new();
let mut sec = SecondaryMap::new();
let ka = sm.insert(()); sec.insert(ka, "butter");
let kb = sm.insert(()); sec.insert(kb, "apples");
let [a, b] = unsafe { sec.get_disjoint_unchecked_mut([ka, kb]) };
std::mem::swap(a, b);
assert_eq!(sec[ka], "apples");
assert_eq!(sec[kb], "butter");
```

--------------------------------

### Get Mutable Reference (Unchecked) in Rust

Source: https://docs.rs/slotmap/latest/slotmap/secondary/struct.SecondaryMap

This function retrieves a mutable reference to a value in the secondary map, without bounds or version checking. It is unsafe and should only be used when the key is known to exist. The example demonstrates how to use the function and the potential dangers if used incorrectly.

```Rust
let mut sm = SlotMap::new();
let key = sm.insert("foo");
let mut sec = SecondaryMap::new();
sec.insert(key, "bar");
unsafe { *sec.get_unchecked_mut(key) = "baz" };
assert_eq!(sec[key], "baz");
sec.remove(key);
// sec.get_unchecked_mut(key) is now dangerous!
```

--------------------------------

### Implement CloneToUninit for generic types

Source: https://docs.rs/slotmap/latest/slotmap/sparse_secondary/struct.SparseSecondaryMap_search=

Provides an experimental, nightly-only method `clone_to_uninit` for types that implement `Clone`. This allows for efficient copying of data into uninitialized memory.

```rust
impl<T> CloneToUninit for T
where
    T: Clone,
{
    unsafe fn clone_to_uninit(&self, dest: *mut u8) {
        // Implementation details omitted for brevity
        unimplemented!();
    }
}
```

--------------------------------

### Get Disjoint Mutable References in HopSlotMap

Source: https://docs.rs/slotmap/latest/slotmap/hop/struct.HopSlotMap

Demonstrates the `get_disjoint_mut` method for safely obtaining mutable references to multiple values corresponding to given keys. It returns `None` if any key is invalid or if the keys are not disjoint. The example shows swapping values after successful retrieval.

```rust
let mut sm = HopSlotMap::new();
let ka = sm.insert("butter");
let kb = sm.insert("apples");
let kc = sm.insert("charlie");
sm.remove(kc); // Make key c invalid.
assert_eq!(sm.get_disjoint_mut([ka, kb, kc]), None); // Has invalid key.
assert_eq!(sm.get_disjoint_mut([ka, ka]), None); // Not disjoint.
let [a, b] = sm.get_disjoint_mut([ka, kb]).unwrap();
std::mem::swap(a, b);
assert_eq!(sm[ka], "apples");
assert_eq!(sm[kb], "butter");
```

--------------------------------

### Experimental and Nightly Features

Source: https://docs.rs/slotmap/latest/slotmap/dense/struct.IntoIter_search=std%3A%3Avec

Documentation for iterator adapters that are currently experimental or only available on the nightly Rust toolchain.

```APIDOC
## Iterator Adapters: Experimental and Nightly Features

### Description
This section covers iterator adapters that are considered experimental or are gated behind the nightly Rust toolchain. Use these with caution as they may change or be removed in future versions.

### Methods

#### `map_windows<F, R, const N: usize>(f: F)`
- **Description**: Calls the given function `f` for each contiguous window of size `N` over `self` and returns an iterator over the outputs of `f`. Like `slice::windows()`, the windows during mapping overlap as well. This is a nightly-only experimental API.
- **Method**: `map_windows`
- **Endpoint**: N/A (Iterator method)
- **Parameters**:
  - **Path Parameters**: None
  - **Query Parameters**: None
  - **Request Body**: None
- **Request Example**: None
- **Response**:
  - **Success Response (200)**: An iterator over the results of applying `f` to each window.
- **Response Example**: None

#### `try_collect<B>()`
- **Description**: Fallibly transforms an iterator into a collection, short-circuiting if a failure is encountered. The item type must implement `Try`, and the residual type must implement `Residual`. This is a nightly-only experimental API.
- **Method**: `try_collect`
- **Endpoint**: N/A (Iterator method)
- **Parameters**:
  - **Path Parameters**: None
  - **Query Parameters**: None
  - **Request Body**: None
- **Request Example**: None
- **Response**:
  - **Success Response (200)**: A collection of type `B` or a residual type indicating failure.
- **Response Example**: None

#### `collect_into<E>(collection: &mut E)`
- **Description**: Collects all the items from an iterator into a mutable collection. The collection type `E` must implement `Extend`. This is a nightly-only experimental API.
- **Method**: `collect_into`
- **Endpoint**: N/A (Iterator method)
- **Parameters**:
  - **Path Parameters**: None
  - **Query Parameters**: None
  - **Request Body**: None
- **Request Example**: None
- **Response**:
  - **Success Response (200)**: A mutable reference to the collection `E` after items have been added.
- **Response Example**: None

#### `is_partitioned<P>(predicate: P)`
- **Description**: Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return `true` precede all those that return `false`. This is a nightly-only experimental API.
- **Method**: `is_partitioned`
- **Endpoint**: N/A (Iterator method)
- **Parameters**:
  - **Path Parameters**: None
  - **Query Parameters**: None
  - **Request Body**: None
- **Request Example**: None
- **Response**:
  - **Success Response (200)**: A boolean value indicating whether the iterator is partitioned.
- **Response Example**: None
```

--------------------------------

### Get Disjoint Mutable References in Rust

Source: https://docs.rs/slotmap/latest/slotmap/secondary/struct.SecondaryMap

This function retrieves mutable references to values corresponding to given keys, ensuring they are valid and disjoint. It returns `None` if any key is invalid or if keys are not disjoint. The example shows how to use the function to swap values and handle potential errors.

```Rust
let mut sm = SlotMap::new();
let mut sec = SecondaryMap::new();
let ka = sm.insert(()); sec.insert(ka, "butter");
let kb = sm.insert(()); sec.insert(kb, "apples");
let kc = sm.insert(()); sec.insert(kc, "charlie");
sec.remove(kc); // Make key c invalid.
assert_eq!(sec.get_disjoint_mut([ka, kb, kc]), None); // Has invalid key.
assert_eq!(sec.get_disjoint_mut([ka, ka]), None); // Not disjoint.
let [a, b] = sec.get_disjoint_mut([ka, kb]).unwrap();
std::mem::swap(a, b);
assert_eq!(sec[ka], "apples");
assert_eq!(sec[kb], "butter");
```

--------------------------------

### SlotMap Initialization with Custom Key Type

Source: https://docs.rs/slotmap/latest/slotmap/basic/struct.SlotMap

Illustrates creating a SlotMap with a custom key type, allowing for more specific key management. Requires defining a new key type using `new_key_type!` macro.

```rust
new_key_type! {
    struct PositionKey;
}
let mut positions: SlotMap<PositionKey, i32> = SlotMap::with_key();
```

--------------------------------

### Unsafe Get Disjoint Mutable References in HopSlotMap

Source: https://docs.rs/slotmap/latest/slotmap/hop/struct.HopSlotMap

Illustrates the `get_disjoint_unchecked_mut` method, which provides unchecked mutable access to multiple values by key. This unsafe method requires the caller to ensure all keys are valid and distinct. The example swaps values using the obtained mutable references.

```rust
let mut sm = HopSlotMap::new();
let ka = sm.insert("butter");
let kb = sm.insert("apples");
let [a, b] = unsafe { sm.get_disjoint_unchecked_mut([ka, kb]) };
std::mem::swap(a, b);
assert_eq!(sm[ka], "apples");
assert_eq!(sm[kb], "butter");
```

--------------------------------

### Any Implementation

Source: https://docs.rs/slotmap/latest/slotmap/struct.HopSlotMap_search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Provides runtime type information for the HopSlotMap.

```APIDOC
## GET /websites/rs_slotmap/type_id

### Description
Gets the `TypeId` of `self`, providing runtime type information.

### Method
GET

### Endpoint
/websites/rs_slotmap/type_id

### Parameters
#### Query Parameters
- `self` (T) - Required - The instance for which to get the `TypeId`.

### Request Example
```json
{
  "self": "<HopSlotMap instance>"
}
```

### Response
#### Success Response (200)
- `TypeId` - The unique identifier for the type of `self`.

#### Response Example
```json
{
  "type_id": "<type_id_string>"
}
```
```

--------------------------------

### Unsafe Get Mutable Value Without Bounds Checking in HopSlotMap

Source: https://docs.rs/slotmap/latest/slotmap/hop/struct.HopSlotMap

Shows the `get_unchecked_mut` method, which provides unchecked mutable access to a value by key. Similar to `get_unchecked`, this method is unsafe and requires the caller to ensure the key's validity to prevent undefined behavior. The example modifies a string value.

```rust
let mut sm = HopSlotMap::new();
let key = sm.insert("foo");
unsafe { *sm.get_unchecked_mut(key) = "bar" };
assert_eq!(sm[key], "bar");
sm.remove(key);
// sm.get_unchecked_mut(key) is now dangerous!
```

--------------------------------

### CloneToUninit Implementation

Source: https://docs.rs/slotmap/latest/slotmap/struct.SecondaryMap

Details the nightly-only experimental `clone_to_uninit` method for types implementing the `Clone` trait.

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

### Description
Performs copy-assignment from `self` to `dest`. This is a nightly-only experimental API.

### Method
`unsafe fn`

### Endpoint
N/A (Standard Library Implementation)

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
None

### Response
None

#### Success Response (200)
None

#### Response Example
None
```

--------------------------------

### SlotMap and SparseSecondaryMap Initialization and Basic Operations (Rust)

Source: https://docs.rs/slotmap/latest/src/slotmap/sparse_secondary.rs

Demonstrates how to initialize a SlotMap and a SparseSecondaryMap, insert key-value pairs, and retrieve or remove values using keys. This example highlights the basic usage pattern for these data structures.

```Rust
# use slotmap::*
let mut sm = SlotMap::new();
let key = sm.insert("foo");
let mut sec = SparseSecondaryMap::new();
sec.insert(key, "bar");
assert_eq!(sec.get(key), Some(&"bar"));
sec.remove(key);
assert_eq!(sec.get(key), None);
```

--------------------------------

### SparseSecondaryMap Blanket Implementations

Source: https://docs.rs/slotmap/latest/slotmap/sparse_secondary/struct.SparseSecondaryMap

Details blanket implementations applicable to SparseSecondaryMap, such as Any, Borrow, CloneToUninit, From, Into, ToOwned, TryFrom, and TryInto.

```APIDOC
## Blanket Implementations for SparseSecondaryMap<K, V, S>

### Description
This section outlines blanket implementations that apply to `SparseSecondaryMap` due to its generic nature and adherence to other traits. These include traits for runtime type information, borrowing, cloning, conversions, and ownership management.

### Implemented Traits and Methods
- **Any**: Provides `type_id()` for runtime type identification.
- **Borrow<T>**: Provides `borrow()` for immutable borrowing.
- **BorrowMut<T>**: Provides `borrow_mut()` for mutable borrowing.
- **CloneToUninit**: (Nightly-only experimental) Provides `clone_to_uninit()` for copying to uninitialized memory.
- **From<T>**: Provides `from()` for creating a type from another.
- **Into<U>**: Provides `into()` for converting a type into another (requires `U: From<T>`).
- **ToOwned**: Provides `to_owned()` and `clone_into()` for creating owned versions.
- **TryFrom<U>**: Provides `try_from()` for fallible conversions from another type.
- **TryInto<U>**: Provides `try_into()` for fallible conversions into another type.

### Endpoint
N/A (These are trait implementations, not REST endpoints)

### Parameters
None

### Request Body
None

### Response
#### Success Response (N/A)
- **Method Availability**: The specified methods are available for `SparseSecondaryMap` instances if the generic constraints are met.

### Request Example
```rust
// Example demonstrating TryInto
let map: SparseSecondaryMap<_, _> = /* ... */;

// Assuming a compatible target type exists
// let converted_map: TargetType = map.try_into().expect("Conversion failed");
```

### Response Example
```json
// No direct JSON response, indicates availability of blanket implementations
```
```

--------------------------------

### Occupied Entry Get Value

Source: https://docs.rs/slotmap/latest/src/slotmap/secondary.rs_search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Gets an immutable reference to the value within an occupied entry.

```APIDOC
## GET /websites/rs_slotmap/entry/get

### Description
Gets an immutable reference to the value in an occupied entry.

### Method
GET

### Endpoint
`/websites/rs_slotmap/entry/get`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```json
{
  "example": "Not applicable for this operation"
}
```

### Response
#### Success Response (200)
- **value** (&V) - A reference to the value within the occupied entry.

#### Response Example
```json
{
  "value": "example_value"
}
```
```

--------------------------------

### DenseSlotMap Initialization with Custom Key (Rust)

Source: https://docs.rs/slotmap/latest/slotmap/dense/struct.DenseSlotMap

Shows how to initialize a DenseSlotMap with a custom key type, allowing for more specific key management. It also demonstrates initializing with both a custom key and a specified capacity.

```Rust
use slotmap::{DenseSlotMap, Key};

// Define a custom key type
slotmap::new_key_type! {
    struct PositionKey;
}

// Construct a new, empty DenseSlotMap with a custom key type
let mut positions: DenseSlotMap<PositionKey, i32> = DenseSlotMap::with_key();

// Define another custom key type
slotmap::new_key_type! {
    struct MessageKey;
}

// Create an empty DenseSlotMap with capacity and a custom key type
let mut messages: DenseSlotMap<MessageKey, &str> = DenseSlotMap::with_capacity_and_key(3);
let welcome_key: MessageKey = messages.insert("Welcome");
let good_day_key = messages.insert("Good day");
let hello_key = messages.insert("Hello");

```

--------------------------------

### Occupied Entry Get Mutable Value

Source: https://docs.rs/slotmap/latest/src/slotmap/secondary.rs_search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Gets a mutable reference to the value within an occupied entry.

```APIDOC
## PUT /websites/rs_slotmap/entry/get_mut

### Description
Gets a mutable reference to the value in an occupied entry.

### Method
PUT

### Endpoint
`/websites/rs_slotmap/entry/get_mut`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```json
{
  "example": "Not applicable for this operation"
}
```

### Response
#### Success Response (200)
- **value** (&mut V) - A mutable reference to the value within the occupied entry.

#### Response Example
```json
{
  "value": "modified_value"
}
```
```

--------------------------------

### TryFrom and TryInto Implementations

Source: https://docs.rs/slotmap/latest/slotmap/struct.SecondaryMap

Explains the `TryFrom<U>` and `TryInto<U>` traits for fallible type conversions.

```APIDOC
#### type Error = Infallible

### Description
The type returned in the event of a conversion error for `TryFrom`.

#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

### Description
Performs the conversion. Returns a `Result` which is `Ok` on success and `Err` on failure.

### Method
`fn`

### Endpoint
N/A (Standard Library Implementation)

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
None

### Response
None

#### Success Response (200)
None

#### Response Example
None

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

### Description
The type returned in the event of a conversion error for `TryInto`.

#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

### Description
Performs the conversion. Returns a `Result` which is `Ok` on success and `Err` on failure.

### Method
`fn`

### Endpoint
N/A (Standard Library Implementation)

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
None

### Response
None

#### Success Response (200)
None

#### Response Example
None
```

--------------------------------

### SlotMap Detach, Reattach, and Get

Source: https://docs.rs/slotmap/latest/slotmap/struct.SlotMap_search=

Illustrates how to temporarily remove a key using `detach`, reattach it with `reattach`, and check its presence with `get`.

```APIDOC
## SlotMap Detach and Reattach

### Description
Demonstrates the temporary removal of a key using `detach` and its subsequent reattachment using `reattach`. Also shows how to retrieve values using `get`.

### Method
POST /slotmap/detach, POST /slotmap/reattach, GET /slotmap/get

### Endpoint
`/slotmap`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
* `key` (KeyType) - Required - The key to detach or reattach.
* `value` (any) - Required - The new value to associate with the key upon reattachment.

### Request Example
```json
{
  "action": "detach",
  "key": "some_key"
}
```
```json
{
  "action": "reattach",
  "key": "some_key",
  "value": 100
}
```
```json
{
  "action": "get",
  "key": "some_key"
}
```

### Response
#### Success Response (200)
* `value` (any) - The value associated with the detached key, if found.
* `exists` (boolean) - Indicates if the key exists after reattachment or get operation.

#### Response Example
```json
{
  "value": 42
}
```
```json
{
  "exists": true
}
```
```

--------------------------------

### Getting the Length of a SecondaryMap (Rust)

Source: https://docs.rs/slotmap/latest/slotmap/secondary/struct.SecondaryMap

Illustrates how to get the number of elements currently stored in a SecondaryMap. This is useful for checking the size of the map.

```rust
let mut sm = SlotMap::new();
let k = sm.insert(4);
let mut squared = SecondaryMap::new();
assert_eq!(squared.len(), 0);
squared.insert(k, 16);
assert_eq!(squared.len(), 1);
```