Trait Sub

1.0.0 · Source

pub trait Sub<Rhs = Self> {
    type Output;

    // Required method
    fn sub(self, rhs: Rhs) -> Self::Output;
}

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

§`Sub`tractable 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 });

Required Associated Types§

1.0.0 · Source

type Output

The resulting type after applying the - operator.

Required Methods§

1.0.0 · Source

fn sub(self, rhs: Rhs) -> Self::Output

Performs the - operation.

§Example

assert_eq!(12 - 1, 11);

Implementors§

Source §

impl Sub for Expr

This does not overflow or underflow at all, as all possible output fits in the range of TimeDelta.

The implementation is a wrapper around NaiveDate::signed_duration_since.

§Example

use chrono::{NaiveDate, TimeDelta};

let from_ymd = |y, m, d| NaiveDate::from_ymd_opt(y, m, d).unwrap();

assert_eq!(from_ymd(2014, 1, 1) - from_ymd(2014, 1, 1), TimeDelta::zero());
assert_eq!(from_ymd(2014, 1, 1) - from_ymd(2013, 12, 31), TimeDelta::try_days(1).unwrap());
assert_eq!(from_ymd(2014, 1, 1) - from_ymd(2014, 1, 2), TimeDelta::try_days(-1).unwrap());
assert_eq!(from_ymd(2014, 1, 1) - from_ymd(2013, 9, 23), TimeDelta::try_days(100).unwrap());
assert_eq!(from_ymd(2014, 1, 1) - from_ymd(2013, 1, 1), TimeDelta::try_days(365).unwrap());
assert_eq!(
    from_ymd(2014, 1, 1) - from_ymd(2010, 1, 1),
    TimeDelta::try_days(365 * 4 + 1).unwrap()
);
assert_eq!(
    from_ymd(2014, 1, 1) - from_ymd(1614, 1, 1),
    TimeDelta::try_days(365 * 400 + 97).unwrap()
);

Source §

type Output = TimeDelta

Source §

impl Sub for NaiveDateTime

Subtracts another NaiveDateTime from the current date and time. This does not overflow or underflow at all.

As a part of Chrono’s leap second handling, the subtraction assumes that there is no leap second ever, except when any of the NaiveDateTimes themselves represents a leap second in which case the assumption becomes that there are exactly one (or two) leap second(s) ever.

The implementation is a wrapper around NaiveDateTime::signed_duration_since.

§Example

use chrono::{NaiveDate, TimeDelta};

let from_ymd = |y, m, d| NaiveDate::from_ymd_opt(y, m, d).unwrap();

let d = from_ymd(2016, 7, 8);
assert_eq!(
    d.and_hms_opt(3, 5, 7).unwrap() - d.and_hms_opt(2, 4, 6).unwrap(),
    TimeDelta::try_seconds(3600 + 60 + 1).unwrap()
);

// July 8 is 190th day in the year 2016
let d0 = from_ymd(2016, 1, 1);
assert_eq!(
    d.and_hms_milli_opt(0, 7, 6, 500).unwrap() - d0.and_hms_opt(0, 0, 0).unwrap(),
    TimeDelta::try_seconds(189 * 86_400 + 7 * 60 + 6).unwrap()
        + TimeDelta::try_milliseconds(500).unwrap()
);

Leap seconds are handled, but the subtraction assumes that no other leap seconds happened.

let leap = from_ymd(2015, 6, 30).and_hms_milli_opt(23, 59, 59, 1_500).unwrap();
assert_eq!(
    leap - from_ymd(2015, 6, 30).and_hms_opt(23, 0, 0).unwrap(),
    TimeDelta::try_seconds(3600).unwrap() + TimeDelta::try_milliseconds(500).unwrap()
);
assert_eq!(
    from_ymd(2015, 7, 1).and_hms_opt(1, 0, 0).unwrap() - leap,
    TimeDelta::try_seconds(3600).unwrap() - TimeDelta::try_milliseconds(500).unwrap()
);

Source §

type Output = TimeDelta

Source §

impl Sub for NaiveTime

Subtracts another NaiveTime from the current time. Returns a TimeDelta within +/- 1 day. This does not overflow or underflow at all.

As a part of Chrono’s leap second handling, the subtraction assumes that there is no leap second ever, except when any of the NaiveTimes themselves represents a leap second in which case the assumption becomes that there are exactly one (or two) leap second(s) ever.

The implementation is a wrapper around NaiveTime::signed_duration_since.

§Example

use chrono::{NaiveTime, TimeDelta};

let from_hmsm = |h, m, s, milli| NaiveTime::from_hms_milli_opt(h, m, s, milli).unwrap();

assert_eq!(from_hmsm(3, 5, 7, 900) - from_hmsm(3, 5, 7, 900), TimeDelta::zero());
assert_eq!(
    from_hmsm(3, 5, 7, 900) - from_hmsm(3, 5, 7, 875),
    TimeDelta::try_milliseconds(25).unwrap()
);
assert_eq!(
    from_hmsm(3, 5, 7, 900) - from_hmsm(3, 5, 6, 925),
    TimeDelta::try_milliseconds(975).unwrap()
);
assert_eq!(
    from_hmsm(3, 5, 7, 900) - from_hmsm(3, 5, 0, 900),
    TimeDelta::try_seconds(7).unwrap()
);
assert_eq!(
    from_hmsm(3, 5, 7, 900) - from_hmsm(3, 0, 7, 900),
    TimeDelta::try_seconds(5 * 60).unwrap()
);
assert_eq!(
    from_hmsm(3, 5, 7, 900) - from_hmsm(0, 5, 7, 900),
    TimeDelta::try_seconds(3 * 3600).unwrap()
);
assert_eq!(
    from_hmsm(3, 5, 7, 900) - from_hmsm(4, 5, 7, 900),
    TimeDelta::try_seconds(-3600).unwrap()
);
assert_eq!(
    from_hmsm(3, 5, 7, 900) - from_hmsm(2, 4, 6, 800),
    TimeDelta::try_seconds(3600 + 60 + 1).unwrap() + TimeDelta::try_milliseconds(100).unwrap()
);

Leap seconds are handled, but the subtraction assumes that there were no other leap seconds happened.

assert_eq!(from_hmsm(3, 0, 59, 1_000) - from_hmsm(3, 0, 59, 0), TimeDelta::try_seconds(1).unwrap());
assert_eq!(from_hmsm(3, 0, 59, 1_500) - from_hmsm(3, 0, 59, 0),
           TimeDelta::try_milliseconds(1500).unwrap());
assert_eq!(from_hmsm(3, 0, 59, 1_000) - from_hmsm(3, 0, 0, 0), TimeDelta::try_seconds(60).unwrap());
assert_eq!(from_hmsm(3, 0, 0, 0) - from_hmsm(2, 59, 59, 1_000), TimeDelta::try_seconds(1).unwrap());
assert_eq!(from_hmsm(3, 0, 59, 1_000) - from_hmsm(2, 59, 59, 1_000),
           TimeDelta::try_seconds(61).unwrap());

Z0 - Z0 = Z0

Source §

type Output = Z0

Source §

impl Sub for UTerm

impl Sub<Duration> for NaiveDateTime

Subtract std::time::Duration from NaiveDateTime.

As a part of Chrono’s [leap second handling] the subtraction assumes that there is no leap second ever, except when the NaiveDateTime itself represents a leap second in which case the assumption becomes that there is exactly a single leap second ever.

§Panics

§Panics

Panics if the resulting date would be out of range. Consider using NaiveDate::checked_sub_signed to get an Option instead.

§Example

use chrono::{NaiveDate, TimeDelta};

let from_ymd = |y, m, d| NaiveDate::from_ymd_opt(y, m, d).unwrap();

assert_eq!(from_ymd(2014, 1, 1) - TimeDelta::zero(), from_ymd(2014, 1, 1));
assert_eq!(from_ymd(2014, 1, 1) - TimeDelta::try_seconds(86399).unwrap(), from_ymd(2014, 1, 1));
assert_eq!(
    from_ymd(2014, 1, 1) - TimeDelta::try_seconds(-86399).unwrap(),
    from_ymd(2014, 1, 1)
);
assert_eq!(from_ymd(2014, 1, 1) - TimeDelta::try_days(1).unwrap(), from_ymd(2013, 12, 31));
assert_eq!(from_ymd(2014, 1, 1) - TimeDelta::try_days(-1).unwrap(), from_ymd(2014, 1, 2));
assert_eq!(from_ymd(2014, 1, 1) - TimeDelta::try_days(364).unwrap(), from_ymd(2013, 1, 2));
assert_eq!(
    from_ymd(2014, 1, 1) - TimeDelta::try_days(365 * 4 + 1).unwrap(),
    from_ymd(2010, 1, 1)
);
assert_eq!(
    from_ymd(2014, 1, 1) - TimeDelta::try_days(365 * 400 + 97).unwrap(),
    from_ymd(1614, 1, 1)
);

Source §

type Output = NaiveDate

Source §

impl Sub<TimeDelta> for NaiveDateTime

Subtract TimeDelta from NaiveDateTime.

This is the same as the addition with a negated TimeDelta.

As a part of Chrono’s leap second handling the subtraction assumes that there is no leap second ever, except when the NaiveDateTime itself represents a leap second in which case the assumption becomes that there is exactly a single leap second ever.

§Panics

Panics if the resulting date would be out of range. Consider using NaiveDateTime::checked_sub_signed to get an Option instead.

§Example

use chrono::{NaiveDate, TimeDelta};

let from_ymd = |y, m, d| NaiveDate::from_ymd_opt(y, m, d).unwrap();

let d = from_ymd(2016, 7, 8);
let hms = |h, m, s| d.and_hms_opt(h, m, s).unwrap();
assert_eq!(hms(3, 5, 7) - TimeDelta::zero(), hms(3, 5, 7));
assert_eq!(hms(3, 5, 7) - TimeDelta::try_seconds(1).unwrap(), hms(3, 5, 6));
assert_eq!(hms(3, 5, 7) - TimeDelta::try_seconds(-1).unwrap(), hms(3, 5, 8));
assert_eq!(hms(3, 5, 7) - TimeDelta::try_seconds(3600 + 60).unwrap(), hms(2, 4, 7));
assert_eq!(
    hms(3, 5, 7) - TimeDelta::try_seconds(86_400).unwrap(),
    from_ymd(2016, 7, 7).and_hms_opt(3, 5, 7).unwrap()
);
assert_eq!(
    hms(3, 5, 7) - TimeDelta::try_days(365).unwrap(),
    from_ymd(2015, 7, 9).and_hms_opt(3, 5, 7).unwrap()
);

let hmsm = |h, m, s, milli| d.and_hms_milli_opt(h, m, s, milli).unwrap();
assert_eq!(hmsm(3, 5, 7, 450) - TimeDelta::try_milliseconds(670).unwrap(), hmsm(3, 5, 6, 780));

Leap seconds are handled, but the subtraction assumes that it is the only leap second happened.

let leap = hmsm(3, 5, 59, 1_300);
assert_eq!(leap - TimeDelta::zero(), hmsm(3, 5, 59, 1_300));
assert_eq!(leap - TimeDelta::try_milliseconds(200).unwrap(), hmsm(3, 5, 59, 1_100));
assert_eq!(leap - TimeDelta::try_milliseconds(500).unwrap(), hmsm(3, 5, 59, 800));
assert_eq!(leap - TimeDelta::try_seconds(60).unwrap(), hmsm(3, 5, 0, 300));
assert_eq!(leap - TimeDelta::try_days(1).unwrap(),
           from_ymd(2016, 7, 7).and_hms_milli_opt(3, 6, 0, 300).unwrap());

Source §

type Output = NaiveDateTime

Source §

impl Sub<TimeDelta> for NaiveTime

Subtract TimeDelta from NaiveTime.

This wraps around and never overflows or underflows. In particular the subtraction ignores integral number of days. This is the same as addition with a negated TimeDelta.

As a part of Chrono’s leap second handling, the subtraction assumes that there is no leap second ever, except when the NaiveTime itself represents a leap second in which case the assumption becomes that there is exactly a single leap second ever.

§Example

use chrono::{NaiveTime, TimeDelta};

let from_hmsm = |h, m, s, milli| NaiveTime::from_hms_milli_opt(h, m, s, milli).unwrap();

assert_eq!(from_hmsm(3, 5, 7, 0) - TimeDelta::zero(), from_hmsm(3, 5, 7, 0));
assert_eq!(from_hmsm(3, 5, 7, 0) - TimeDelta::try_seconds(1).unwrap(), from_hmsm(3, 5, 6, 0));
assert_eq!(
    from_hmsm(3, 5, 7, 0) - TimeDelta::try_seconds(60 + 5).unwrap(),
    from_hmsm(3, 4, 2, 0)
);
assert_eq!(
    from_hmsm(3, 5, 7, 0) - TimeDelta::try_seconds(2 * 60 * 60 + 6 * 60).unwrap(),
    from_hmsm(0, 59, 7, 0)
);
assert_eq!(
    from_hmsm(3, 5, 7, 0) - TimeDelta::try_milliseconds(80).unwrap(),
    from_hmsm(3, 5, 6, 920)
);
assert_eq!(
    from_hmsm(3, 5, 7, 950) - TimeDelta::try_milliseconds(280).unwrap(),
    from_hmsm(3, 5, 7, 670)
);

The subtraction wraps around.

assert_eq!(from_hmsm(3, 5, 7, 0) - TimeDelta::try_seconds(8*60*60).unwrap(), from_hmsm(19, 5, 7, 0));
assert_eq!(from_hmsm(3, 5, 7, 0) - TimeDelta::try_days(800).unwrap(), from_hmsm(3, 5, 7, 0));

Leap seconds are handled, but the subtraction assumes that it is the only leap second happened.

let leap = from_hmsm(3, 5, 59, 1_300);
assert_eq!(leap - TimeDelta::zero(), from_hmsm(3, 5, 59, 1_300));
assert_eq!(leap - TimeDelta::try_milliseconds(200).unwrap(), from_hmsm(3, 5, 59, 1_100));
assert_eq!(leap - TimeDelta::try_milliseconds(500).unwrap(), from_hmsm(3, 5, 59, 800));
assert_eq!(leap - TimeDelta::try_seconds(60).unwrap(), from_hmsm(3, 5, 0, 300));
assert_eq!(leap - TimeDelta::try_days(1).unwrap(), from_hmsm(3, 6, 0, 300));

Source §

impl Sub<B0> for UTerm

UTerm - B0 = Term

Source §

type Output = UTerm

Source §

impl Sub<B1> for UInt<UTerm, B1>

UInt<UTerm, B1> - B1 = UTerm

impl<Tz> Sub<Days> for DateTime<Tz>
where Tz: TimeZone,

Subtract Days from DateTime.

§Panics

Panics if:

The resulting date would be out of range.
The local time at the resulting date does not exist or is ambiguous, for example during a daylight saving time transition.

Strongly consider using DateTime<Tz>::checked_sub_days to get an Option instead.

Source §

type Output = DateTime<Tz>

Source §

impl<Tz> Sub<FixedOffset> for DateTime<Tz>
where Tz: TimeZone,

Subtract FixedOffset from the datetime value of DateTime (offset remains unchanged).

§Panics

Panics if the resulting date would be out of range.

Source §

Trait SubCopy item path

§Examples

§Subtractable points

§Implementing Sub with generics

Required Associated Types§

type Output

Required Methods§

fn sub(self, rhs: Rhs) -> Self::Output

§Example

Implementors§

impl Sub for Expr

type Output = Expr

impl Sub for f16

type Output = f16

impl Sub for f32

type Output = f32

impl Sub for f64

type Output = f64

impl Sub for f128

type Output = f128

impl Sub for i8

type Output = i8

impl Sub for i16

type Output = i16

impl Sub for i32

type Output = i32

impl Sub for i64

type Output = i64

impl Sub for i128

type Output = i128

impl Sub for isize

type Output = isize

impl Sub for u8

type Output = u8

impl Sub for u16

type Output = u16

impl Sub for u32

type Output = u32

impl Sub for u64

type Output = u64

impl Sub for u128

type Output = u128

impl Sub for usize

type Output = usize

impl Sub for IntervalDayTime

type Output = IntervalDayTime

impl Sub for IntervalMonthDayNano

type Output = IntervalMonthDayNano

impl Sub for i256

type Output = i256

impl Sub for Assume

type Output = Assume

impl Sub for Saturating<i8>

type Output = Saturating<i8>

impl Sub for Saturating<i16>

type Output = Saturating<i16>

impl Sub for Saturating<i32>

type Output = Saturating<i32>

impl Sub for Saturating<i64>

type Output = Saturating<i64>

impl Sub for Saturating<i128>

type Output = Saturating<i128>

impl Sub for Saturating<isize>

type Output = Saturating<isize>

impl Sub for Saturating<u8>

type Output = Saturating<u8>

impl Sub for Saturating<u16>

type Output = Saturating<u16>

impl Sub for Saturating<u32>

type Output = Saturating<u32>

impl Sub for Saturating<u64>

type Output = Saturating<u64>

impl Sub for Saturating<u128>

type Output = Saturating<u128>

impl Sub for Saturating<usize>

type Output = Saturating<usize>

impl Sub for Wrapping<i8>

type Output = Wrapping<i8>

impl Sub for Wrapping<i16>

type Output = Wrapping<i16>

Trait Sub

§`Sub`tractable points

§Implementing `Sub` with generics