Trait Len

pub trait Len<L> {
    // Required methods
    fn len(&self) -> L;
    fn len_into_u64(len: L) -> u64;
    fn zero_len() -> L;
}

Types for values that have a length.

At present, these are:

type	length description
&str, String	length in bytes
Vec<T>	number of elements in the vector
HashMap<K, V>, BTreeMap<K, V>	number of key/value pairs in the map
TempFile	length of the file in bytes
Option<T> where T: Len	length of T or 0 if None
form::Result<'_, T>	length of T or 0 if Err

Required Methods

fn len(&self) -> L

The length of the value.

fn len_into_u64(len: L) -> u64

Convert len into u64.

fn zero_len() -> L

The zero value for L.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl Len<usize> for str

fn len(&self) -> usize

fn len_into_u64(len: usize) -> u64

fn zero_len() -> usize

impl<L, T: Len<L> + ?Sized> Len<L> for &T

fn len(&self) -> L

fn len_into_u64(len: L) -> u64

fn zero_len() -> L

Implementors

impl Len<u64> for TempFile<'_>

impl Len<usize> for String

impl Len<ByteUnit> for TempFile<'_>

impl<K, V> Len<usize> for BTreeMap<K, V>

impl<K, V> Len<usize> for HashMap<K, V>

impl<L, T: Len<L>> Len<L> for Option<T>

impl<L, T: Len<L>> Len<L> for Capped<T>

impl<L, T: Len<L>> Len<L> for Json<T>

impl<L, T: Len<L>> Len<L> for MsgPack<T>

impl<L, T: Len<L>> Len<L> for Result<'_, T>

impl<T> Len<usize> for Vec<T>