Expand description
The subtraction operator -.
Note that Rhs is Self by default, but this is not mandatory. For
example, std::time::SystemTime implements Sub<Duration>, which permits
operations of the form SystemTime = SystemTime - Duration.
Examples
Subtractable points
use std::ops::Sub;
#[derive(Debug, Copy, Clone, PartialEq)]
struct Point {
x: i32,
y: i32,
}
impl Sub for Point {
type Output = Self;
fn sub(self, other: Self) -> Self::Output {
Self {
x: self.x - other.x,
y: self.y - other.y,
}
}
}
assert_eq!(Point { x: 3, y: 3 } - Point { x: 2, y: 3 },
Point { x: 1, y: 0 });Implementing Sub with generics
Here is an example of the same Point struct implementing the Sub trait
using generics.
use std::ops::Sub;
#[derive(Debug, PartialEq)]
struct Point<T> {
x: T,
y: T,
}
// Notice that the implementation uses the associated type `Output`.
impl<T: Sub<Output = T>> Sub for Point<T> {
type Output = Self;
fn sub(self, other: Self) -> Self::Output {
Point {
x: self.x - other.x,
y: self.y - other.y,
}
}
}
assert_eq!(Point { x: 2, y: 3 } - Point { x: 1, y: 0 },
Point { x: 1, y: 3 });Associated Types
Required methods
Implementations on Foreign Types
sourceimpl<'_, '_, T, S> Sub<&'_ HashSet<T, S>> for &'_ HashSet<T, S> where
T: Eq + Hash + Clone,
S: BuildHasher + Default,
impl<'_, '_, T, S> Sub<&'_ HashSet<T, S>> for &'_ HashSet<T, S> where
T: Eq + Hash + Clone,
S: BuildHasher + Default,
sourcepub fn sub(self, rhs: &HashSet<T, S>) -> HashSet<T, S>
pub fn sub(self, rhs: &HashSet<T, S>) -> HashSet<T, S>
Returns the difference of self and rhs as a new HashSet<T, S>.
Examples
use std::collections::HashSet;
let a = HashSet::from([1, 2, 3]);
let b = HashSet::from([3, 4, 5]);
let set = &a - &b;
let mut i = 0;
let expected = [1, 2];
for x in &set {
assert!(expected.contains(x));
i += 1;
}
assert_eq!(i, expected.len());type Output = HashSet<T, S>
1.8.0 · sourceimpl Sub<Duration> for SystemTime
impl Sub<Duration> for SystemTime
type Output = SystemTime
pub fn sub(self, dur: Duration) -> SystemTime
1.8.0 · sourceimpl Sub<Instant> for Instant
impl Sub<Instant> for Instant
sourcepub fn sub(self, other: Instant) -> Duration
pub fn sub(self, other: Instant) -> Duration
Returns the amount of time elapsed from another instant to this one, or zero duration if that instant is later than this one.
Panics
Previous rust versions panicked when other was later than self. Currently this
method saturates. Future versions may reintroduce the panic in some circumstances.
See Monotonicity.