# Primitive Type isize1.0.0[−]

## Expand description

The pointer-sized signed integer type.

The size of this primitive is how many bytes it takes to reference any location in memory. For example, on a 32 bit target, this is 4 bytes and on a 64 bit target, this is 8 bytes.

## Implementations

Calculates the complete product `self * rhs`

without the possibility to overflow.

This returns the low-order (wrapping) bits and the high-order (overflow) bits of the result as two separate values, in that order.

##### Examples

Basic usage:

Please note that this example is shared between integer types.
Which explains why `u32`

is used here.

```
#![feature(bigint_helper_methods)]
assert_eq!(5u32.widening_mul(2), (10, 0));
assert_eq!(1_000_000_000u32.widening_mul(10), (1410065408, 2));
```

RunCalculates the “full multiplication” `self * rhs + carry`

without the possibility to overflow.

This returns the low-order (wrapping) bits and the high-order (overflow) bits of the result as two separate values, in that order.

Performs “long multiplication” which takes in an extra amount to add, and may return an additional amount of overflow. This allows for chaining together multiple multiplications to create “big integers” which represent larger values.

##### Examples

Basic usage:

Please note that this example is shared between integer types.
Which explains why `u32`

is used here.

```
#![feature(bigint_helper_methods)]
assert_eq!(5u32.carrying_mul(2, 0), (10, 0));
assert_eq!(5u32.carrying_mul(2, 10), (20, 0));
assert_eq!(1_000_000_000u32.carrying_mul(10, 0), (1410065408, 2));
assert_eq!(1_000_000_000u32.carrying_mul(10, 10), (1410065418, 2));
```

RunConverts a string slice in a given base to an integer.

The string is expected to be an optional `+`

or `-`

sign followed by digits.
Leading and trailing whitespace represent an error. Digits are a subset of these characters,
depending on `radix`

:

`0-9`

`a-z`

`A-Z`

##### Panics

This function panics if `radix`

is not in the range from 2 to 36.

##### Examples

Basic usage:

`assert_eq!(isize::from_str_radix("A", 16), Ok(10));`

RunShifts the bits to the right by a specified amount, `n`

,
wrapping the truncated bits to the beginning of the resulting
integer.

Please note this isn’t the same operation as the `>>`

shifting operator!

##### Examples

Basic usage:

```
let n = 0x6e10aaisize;
let m = 0xaa00000000006e1;
assert_eq!(n.rotate_right(12), m);
```

RunReverses the order of bits in the integer. The least significant bit becomes the most significant bit, second least-significant bit becomes second most-significant bit, etc.

##### Examples

Basic usage:

```
let n = 0x1234567890123456isize;
let m = n.reverse_bits();
assert_eq!(m, 0x6a2c48091e6a2c48);
assert_eq!(0, 0isize.reverse_bits());
```

RunConverts an integer from big endian to the target’s endianness.

On big endian this is a no-op. On little endian the bytes are swapped.

##### Examples

Basic usage:

```
let n = 0x1Aisize;
if cfg!(target_endian = "big") {
assert_eq!(isize::from_be(n), n)
} else {
assert_eq!(isize::from_be(n), n.swap_bytes())
}
```

RunConverts an integer from little endian to the target’s endianness.

On little endian this is a no-op. On big endian the bytes are swapped.

##### Examples

Basic usage:

```
let n = 0x1Aisize;
if cfg!(target_endian = "little") {
assert_eq!(isize::from_le(n), n)
} else {
assert_eq!(isize::from_le(n), n.swap_bytes())
}
```

Run## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked integer addition. Computes `self + rhs`

, assuming overflow
cannot occur.

##### Safety

This results in undefined behavior when
`self + rhs > isize::MAX`

or `self + rhs < isize::MIN`

,
i.e. when `checked_add`

would return `None`

.

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked integer subtraction. Computes `self - rhs`

, assuming overflow
cannot occur.

##### Safety

This results in undefined behavior when
`self - rhs > isize::MAX`

or `self - rhs < isize::MIN`

,
i.e. when `checked_sub`

would return `None`

.

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked integer multiplication. Computes `self * rhs`

, assuming overflow
cannot occur.

##### Safety

This results in undefined behavior when
`self * rhs > isize::MAX`

or `self * rhs < isize::MIN`

,
i.e. when `checked_mul`

would return `None`

.

Checked Euclidean division. Computes `self.div_euclid(rhs)`

,
returning `None`

if `rhs == 0`

or the division results in overflow.

##### Examples

Basic usage:

```
assert_eq!((isize::MIN + 1).checked_div_euclid(-1), Some(9223372036854775807));
assert_eq!(isize::MIN.checked_div_euclid(-1), None);
assert_eq!((1isize).checked_div_euclid(0), None);
```

RunChecked Euclidean remainder. Computes `self.rem_euclid(rhs)`

, returning `None`

if `rhs == 0`

or the division results in overflow.

##### Examples

Basic usage:

```
assert_eq!(5isize.checked_rem_euclid(2), Some(1));
assert_eq!(5isize.checked_rem_euclid(0), None);
assert_eq!(isize::MIN.checked_rem_euclid(-1), None);
```

Run## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked shift left. Computes `self << rhs`

, assuming that
`rhs`

is less than the number of bits in `self`

.

##### Safety

This results in undefined behavior if `rhs`

is larger than
or equal to the number of bits in `self`

,
i.e. when `checked_shl`

would return `None`

.

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked shift right. Computes `self >> rhs`

, assuming that
`rhs`

is less than the number of bits in `self`

.

##### Safety

This results in undefined behavior if `rhs`

is larger than
or equal to the number of bits in `self`

,
i.e. when `checked_shr`

would return `None`

.

Saturating integer negation. Computes `-self`

, returning `MAX`

if `self == MIN`

instead of overflowing.

##### Examples

Basic usage:

```
assert_eq!(100isize.saturating_neg(), -100);
assert_eq!((-100isize).saturating_neg(), 100);
assert_eq!(isize::MIN.saturating_neg(), isize::MAX);
assert_eq!(isize::MAX.saturating_neg(), isize::MIN + 1);
```

RunSaturating absolute value. Computes `self.abs()`

, returning `MAX`

if `self == MIN`

instead of overflowing.

##### Examples

Basic usage:

```
assert_eq!(100isize.saturating_abs(), 100);
assert_eq!((-100isize).saturating_abs(), 100);
assert_eq!(isize::MIN.saturating_abs(), isize::MAX);
assert_eq!((isize::MIN + 1).saturating_abs(), isize::MAX);
```

RunSaturating integer division. Computes `self / rhs`

, saturating at the
numeric bounds instead of overflowing.

##### Examples

Basic usage:

```
#![feature(saturating_div)]
assert_eq!(5isize.saturating_div(2), 2);
assert_eq!(isize::MAX.saturating_div(-1), isize::MIN + 1);
assert_eq!(isize::MIN.saturating_div(-1), isize::MAX);
```

Run```
#![feature(saturating_div)]
let _ = 1isize.saturating_div(0);
```

RunWrapping (modular) division. Computes `self / rhs`

, wrapping around at the
boundary of the type.

The only case where such wrapping can occur is when one divides `MIN / -1`

on a signed type (where
`MIN`

is the negative minimal value for the type); this is equivalent to `-MIN`

, a positive value
that is too large to represent in the type. In such a case, this function returns `MIN`

itself.

##### Panics

This function will panic if `rhs`

is 0.

##### Examples

Basic usage:

```
assert_eq!(100isize.wrapping_div(10), 10);
assert_eq!((-128i8).wrapping_div(-1), -128);
```

RunWrapping Euclidean division. Computes `self.div_euclid(rhs)`

,
wrapping around at the boundary of the type.

Wrapping will only occur in `MIN / -1`

on a signed type (where `MIN`

is the negative minimal value
for the type). This is equivalent to `-MIN`

, a positive value that is too large to represent in the
type. In this case, this method returns `MIN`

itself.

##### Panics

This function will panic if `rhs`

is 0.

##### Examples

Basic usage:

```
assert_eq!(100isize.wrapping_div_euclid(10), 10);
assert_eq!((-128i8).wrapping_div_euclid(-1), -128);
```

RunWrapping (modular) remainder. Computes `self % rhs`

, wrapping around at the
boundary of the type.

Such wrap-around never actually occurs mathematically; implementation artifacts make `x % y`

invalid for `MIN / -1`

on a signed type (where `MIN`

is the negative minimal value). In such a case,
this function returns `0`

.

##### Panics

This function will panic if `rhs`

is 0.

##### Examples

Basic usage:

```
assert_eq!(100isize.wrapping_rem(10), 0);
assert_eq!((-128i8).wrapping_rem(-1), 0);
```

RunWrapping Euclidean remainder. Computes `self.rem_euclid(rhs)`

, wrapping around
at the boundary of the type.

Wrapping will only occur in `MIN % -1`

on a signed type (where `MIN`

is the negative minimal value
for the type). In this case, this method returns 0.

##### Panics

This function will panic if `rhs`

is 0.

##### Examples

Basic usage:

```
assert_eq!(100isize.wrapping_rem_euclid(10), 0);
assert_eq!((-128i8).wrapping_rem_euclid(-1), 0);
```

RunWrapping (modular) negation. Computes `-self`

, wrapping around at the boundary
of the type.

The only case where such wrapping can occur is when one negates `MIN`

on a signed type (where `MIN`

is the negative minimal value for the type); this is a positive value that is too large to represent
in the type. In such a case, this function returns `MIN`

itself.

##### Examples

Basic usage:

```
assert_eq!(100isize.wrapping_neg(), -100);
assert_eq!(isize::MIN.wrapping_neg(), isize::MIN);
```

RunPanic-free bitwise shift-left; yields `self << mask(rhs)`

, where `mask`

removes
any high-order bits of `rhs`

that would cause the shift to exceed the bitwidth of the type.

Note that this is *not* the same as a rotate-left; the RHS of a wrapping shift-left is restricted to
the range of the type, rather than the bits shifted out of the LHS being returned to the other end.
The primitive integer types all implement a `rotate_left`

function,
which may be what you want instead.

##### Examples

Basic usage:

```
assert_eq!((-1isize).wrapping_shl(7), -128);
assert_eq!((-1isize).wrapping_shl(128), -1);
```

RunPanic-free bitwise shift-right; yields `self >> mask(rhs)`

, where `mask`

removes any high-order bits of `rhs`

that would cause the shift to exceed the bitwidth of the type.

Note that this is *not* the same as a rotate-right; the RHS of a wrapping shift-right is restricted
to the range of the type, rather than the bits shifted out of the LHS being returned to the other
end. The primitive integer types all implement a `rotate_right`

function,
which may be what you want instead.

##### Examples

Basic usage:

```
assert_eq!((-128isize).wrapping_shr(7), -1);
assert_eq!((-128i16).wrapping_shr(64), -128);
```

RunWrapping (modular) absolute value. Computes `self.abs()`

, wrapping around at
the boundary of the type.

The only case where such wrapping can occur is when one takes the absolute value of the negative
minimal value for the type; this is a positive value that is too large to represent in the type. In
such a case, this function returns `MIN`

itself.

##### Examples

Basic usage:

```
assert_eq!(100isize.wrapping_abs(), 100);
assert_eq!((-100isize).wrapping_abs(), 100);
assert_eq!(isize::MIN.wrapping_abs(), isize::MIN);
assert_eq!((-128i8).wrapping_abs() as u8, 128);
```

RunCalculates `self`

+ `rhs`

Returns a tuple of the addition along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would have occurred then the wrapped value is returned.

##### Examples

Basic usage:

```
assert_eq!(5isize.overflowing_add(2), (7, false));
assert_eq!(isize::MAX.overflowing_add(1), (isize::MIN, true));
```

RunCalculates `self + rhs + carry`

without the ability to overflow.

Performs “ternary addition” which takes in an extra bit to add, and may return an additional bit of overflow. This allows for chaining together multiple additions to create “big integers” which represent larger values.

##### Examples

Basic usage

```
#![feature(bigint_helper_methods)]
assert_eq!(5isize.carrying_add(2, false), (7, false));
assert_eq!(5isize.carrying_add(2, true), (8, false));
assert_eq!(isize::MAX.carrying_add(1, false), (isize::MIN, false));
assert_eq!(isize::MAX.carrying_add(1, true), (isize::MIN + 1, false));
```

RunCalculates `self`

+ `rhs`

with an unsigned `rhs`

Returns a tuple of the addition along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would have occurred then the wrapped value is returned.

##### Examples

Basic usage:

```
assert_eq!(1isize.overflowing_add_unsigned(2), (3, false));
assert_eq!((isize::MIN).overflowing_add_unsigned(usize::MAX), (isize::MAX, false));
assert_eq!((isize::MAX - 2).overflowing_add_unsigned(3), (isize::MIN, true));
```

RunCalculates `self`

- `rhs`

Returns a tuple of the subtraction along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would have occurred then the wrapped value is returned.

##### Examples

Basic usage:

```
assert_eq!(5isize.overflowing_sub(2), (3, false));
assert_eq!(isize::MIN.overflowing_sub(1), (isize::MAX, true));
```

RunCalculates `self - rhs - borrow`

without the ability to overflow.

Performs “ternary subtraction” which takes in an extra bit to subtract, and may return an additional bit of overflow. This allows for chaining together multiple subtractions to create “big integers” which represent larger values.

##### Examples

Basic usage

```
#![feature(bigint_helper_methods)]
assert_eq!(5isize.borrowing_sub(2, false), (3, false));
assert_eq!(5isize.borrowing_sub(2, true), (2, false));
assert_eq!(isize::MIN.borrowing_sub(1, false), (isize::MAX, false));
assert_eq!(isize::MIN.borrowing_sub(1, true), (isize::MAX - 1, false));
```

RunCalculates `self`

- `rhs`

with an unsigned `rhs`

Returns a tuple of the subtraction along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would have occurred then the wrapped value is returned.

##### Examples

Basic usage:

```
assert_eq!(1isize.overflowing_sub_unsigned(2), (-1, false));
assert_eq!((isize::MAX).overflowing_sub_unsigned(usize::MAX), (isize::MIN, false));
assert_eq!((isize::MIN + 2).overflowing_sub_unsigned(3), (isize::MAX, true));
```

RunCalculates the multiplication of `self`

and `rhs`

.

Returns a tuple of the multiplication along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would have occurred then the wrapped value is returned.

##### Examples

Basic usage:

```
assert_eq!(5isize.overflowing_mul(2), (10, false));
assert_eq!(1_000_000_000i32.overflowing_mul(10), (1410065408, true));
```

RunCalculates the divisor when `self`

is divided by `rhs`

.

Returns a tuple of the divisor along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would occur then self is returned.

##### Panics

This function will panic if `rhs`

is 0.

##### Examples

Basic usage:

```
assert_eq!(5isize.overflowing_div(2), (2, false));
assert_eq!(isize::MIN.overflowing_div(-1), (isize::MIN, true));
```

RunCalculates the quotient of Euclidean division `self.div_euclid(rhs)`

.

Returns a tuple of the divisor along with a boolean indicating whether an arithmetic overflow would
occur. If an overflow would occur then `self`

is returned.

##### Panics

This function will panic if `rhs`

is 0.

##### Examples

Basic usage:

```
assert_eq!(5isize.overflowing_div_euclid(2), (2, false));
assert_eq!(isize::MIN.overflowing_div_euclid(-1), (isize::MIN, true));
```

RunCalculates the remainder when `self`

is divided by `rhs`

.

Returns a tuple of the remainder after dividing along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would occur then 0 is returned.

##### Panics

This function will panic if `rhs`

is 0.

##### Examples

Basic usage:

```
assert_eq!(5isize.overflowing_rem(2), (1, false));
assert_eq!(isize::MIN.overflowing_rem(-1), (0, true));
```

RunOverflowing Euclidean remainder. Calculates `self.rem_euclid(rhs)`

.

Returns a tuple of the remainder after dividing along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would occur then 0 is returned.

##### Panics

This function will panic if `rhs`

is 0.

##### Examples

Basic usage:

```
assert_eq!(5isize.overflowing_rem_euclid(2), (1, false));
assert_eq!(isize::MIN.overflowing_rem_euclid(-1), (0, true));
```

RunNegates self, overflowing if this is equal to the minimum value.

Returns a tuple of the negated version of self along with a boolean indicating whether an overflow
happened. If `self`

is the minimum value (e.g., `i32::MIN`

for values of type `i32`

), then the
minimum value will be returned again and `true`

will be returned for an overflow happening.

##### Examples

Basic usage:

```
assert_eq!(2isize.overflowing_neg(), (-2, false));
assert_eq!(isize::MIN.overflowing_neg(), (isize::MIN, true));
```

RunShifts self left by `rhs`

bits.

Returns a tuple of the shifted version of self along with a boolean indicating whether the shift value was larger than or equal to the number of bits. If the shift value is too large, then value is masked (N-1) where N is the number of bits, and this value is then used to perform the shift.

##### Examples

Basic usage:

```
assert_eq!(0x1isize.overflowing_shl(4), (0x10, false));
assert_eq!(0x1i32.overflowing_shl(36), (0x10, true));
```

RunShifts self right by `rhs`

bits.

Returns a tuple of the shifted version of self along with a boolean indicating whether the shift value was larger than or equal to the number of bits. If the shift value is too large, then value is masked (N-1) where N is the number of bits, and this value is then used to perform the shift.

##### Examples

Basic usage:

```
assert_eq!(0x10isize.overflowing_shr(4), (0x1, false));
assert_eq!(0x10i32.overflowing_shr(36), (0x1, true));
```

RunComputes the absolute value of `self`

.

Returns a tuple of the absolute version of self along with a boolean indicating whether an overflow happened. If self is the minimum value (e.g., isize::MIN for values of type isize), then the minimum value will be returned again and true will be returned for an overflow happening.

##### Examples

Basic usage:

```
assert_eq!(10isize.overflowing_abs(), (10, false));
assert_eq!((-10isize).overflowing_abs(), (10, false));
assert_eq!((isize::MIN).overflowing_abs(), (isize::MIN, true));
```

RunCalculates the quotient of Euclidean division of `self`

by `rhs`

.

This computes the integer `q`

such that `self = q * rhs + r`

, with
`r = self.rem_euclid(rhs)`

and `0 <= r < abs(rhs)`

.

In other words, the result is `self / rhs`

rounded to the integer `q`

such that `self >= q * rhs`

.
If `self > 0`

, this is equal to round towards zero (the default in Rust);
if `self < 0`

, this is equal to round towards +/- infinity.

##### Panics

This function will panic if `rhs`

is 0 or the division results in overflow.

##### Examples

Basic usage:

```
let a: isize = 7; // or any other integer type
let b = 4;
assert_eq!(a.div_euclid(b), 1); // 7 >= 4 * 1
assert_eq!(a.div_euclid(-b), -1); // 7 >= -4 * -1
assert_eq!((-a).div_euclid(b), -2); // -7 >= 4 * -2
assert_eq!((-a).div_euclid(-b), 2); // -7 >= -4 * 2
```

RunCalculates the least nonnegative remainder of `self (mod rhs)`

.

This is done as if by the Euclidean division algorithm – given
`r = self.rem_euclid(rhs)`

, `self = rhs * self.div_euclid(rhs) + r`

, and
`0 <= r < abs(rhs)`

.

##### Panics

This function will panic if `rhs`

is 0 or the division results in overflow.

##### Examples

Basic usage:

```
let a: isize = 7; // or any other integer type
let b = 4;
assert_eq!(a.rem_euclid(b), 3);
assert_eq!((-a).rem_euclid(b), 1);
assert_eq!(a.rem_euclid(-b), 3);
assert_eq!((-a).rem_euclid(-b), 1);
```

RunCalculates the quotient of `self`

and `rhs`

, rounding the result towards negative infinity.

##### Panics

This function will panic if `rhs`

is 0 or the division results in overflow.

##### Examples

Basic usage:

```
#![feature(int_roundings)]
let a: isize = 8;
let b = 3;
assert_eq!(a.unstable_div_floor(b), 2);
assert_eq!(a.unstable_div_floor(-b), -3);
assert_eq!((-a).unstable_div_floor(b), -3);
assert_eq!((-a).unstable_div_floor(-b), 2);
```

RunCalculates the quotient of `self`

and `rhs`

, rounding the result towards positive infinity.

##### Panics

This function will panic if `rhs`

is 0 or the division results in overflow.

##### Examples

Basic usage:

```
#![feature(int_roundings)]
let a: isize = 8;
let b = 3;
assert_eq!(a.unstable_div_ceil(b), 3);
assert_eq!(a.unstable_div_ceil(-b), -2);
assert_eq!((-a).unstable_div_ceil(b), -2);
assert_eq!((-a).unstable_div_ceil(-b), 3);
```

RunIf `rhs`

is positive, calculates the smallest value greater than or
equal to `self`

that is a multiple of `rhs`

. If `rhs`

is negative,
calculates the largest value less than or equal to `self`

that is a
multiple of `rhs`

.

##### Panics

This function will panic if `rhs`

is 0 or the operation results in overflow.

##### Examples

Basic usage:

```
#![feature(int_roundings)]
assert_eq!(16_isize.unstable_next_multiple_of(8), 16);
assert_eq!(23_isize.unstable_next_multiple_of(8), 24);
assert_eq!(16_isize.unstable_next_multiple_of(-8), 16);
assert_eq!(23_isize.unstable_next_multiple_of(-8), 16);
assert_eq!((-16_isize).unstable_next_multiple_of(8), -16);
assert_eq!((-23_isize).unstable_next_multiple_of(8), -16);
assert_eq!((-16_isize).unstable_next_multiple_of(-8), -16);
assert_eq!((-23_isize).unstable_next_multiple_of(-8), -24);
```

RunIf `rhs`

is positive, calculates the smallest value greater than or
equal to `self`

that is a multiple of `rhs`

. If `rhs`

is negative,
calculates the largest value less than or equal to `self`

that is a
multiple of `rhs`

. Returns `None`

if `rhs`

is zero or the operation
would result in overflow.

##### Examples

Basic usage:

```
#![feature(int_roundings)]
assert_eq!(16_isize.checked_next_multiple_of(8), Some(16));
assert_eq!(23_isize.checked_next_multiple_of(8), Some(24));
assert_eq!(16_isize.checked_next_multiple_of(-8), Some(16));
assert_eq!(23_isize.checked_next_multiple_of(-8), Some(16));
assert_eq!((-16_isize).checked_next_multiple_of(8), Some(-16));
assert_eq!((-23_isize).checked_next_multiple_of(8), Some(-16));
assert_eq!((-16_isize).checked_next_multiple_of(-8), Some(-16));
assert_eq!((-23_isize).checked_next_multiple_of(-8), Some(-24));
assert_eq!(1_isize.checked_next_multiple_of(0), None);
assert_eq!(isize::MAX.checked_next_multiple_of(2), None);
```

RunReturns the logarithm of the number with respect to an arbitrary base, rounded down.

This method might not be optimized owing to implementation details;
`log2`

can produce results more efficiently for base 2, and `log10`

can produce results more efficiently for base 10.

##### Panics

When the number is zero, or if the base is not at least 2; it panics in debug mode and the return value is 0 in release mode.

##### Examples

```
#![feature(int_log)]
assert_eq!(5isize.log(5), 1);
```

RunReturns the logarithm of the number with respect to an arbitrary base, rounded down.

Returns `None`

if the number is negative or zero, or if the base is not at least 2.

This method might not be optimized owing to implementation details;
`checked_log2`

can produce results more efficiently for base 2, and
`checked_log10`

can produce results more efficiently for base 10.

##### Examples

```
#![feature(int_log)]
assert_eq!(5isize.checked_log(5), Some(1));
```

RunComputes the absolute value of `self`

.

##### Overflow behavior

The absolute value of
`isize::MIN`

cannot be represented as an
`isize`

,
and attempting to calculate it will cause an overflow. This means
that code in debug mode will trigger a panic on this case and
optimized code will return
`isize::MIN`

without a panic.

##### Examples

Basic usage:

```
assert_eq!(10isize.abs(), 10);
assert_eq!((-10isize).abs(), 10);
```

RunComputes the absolute difference between `self`

and `other`

.

This function always returns the correct answer without overflow or panics by returning an unsigned integer.

##### Examples

Basic usage:

```
#![feature(int_abs_diff)]
assert_eq!(100isize.abs_diff(80), 20usize);
assert_eq!(100isize.abs_diff(110), 10usize);
assert_eq!((-100isize).abs_diff(80), 180usize);
assert_eq!((-100isize).abs_diff(-120), 20usize);
assert_eq!(isize::MIN.abs_diff(isize::MAX), usize::MAX);
```

RunReturn the memory representation of this integer as a byte array in big-endian (network) byte order.

**Note**: This function returns an array of length 2, 4 or 8 bytes
depending on the target pointer size.

##### Examples

```
let bytes = 0x1234567890123456isize.to_be_bytes();
assert_eq!(bytes, [0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]);
```

RunReturn the memory representation of this integer as a byte array in little-endian byte order.

**Note**: This function returns an array of length 2, 4 or 8 bytes
depending on the target pointer size.

##### Examples

```
let bytes = 0x1234567890123456isize.to_le_bytes();
assert_eq!(bytes, [0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]);
```

RunReturn the memory representation of this integer as a byte array in native byte order.

As the target platform’s native endianness is used, portable code
should use `to_be_bytes`

or `to_le_bytes`

, as appropriate,
instead.

**Note**: This function returns an array of length 2, 4 or 8 bytes
depending on the target pointer size.

##### Examples

```
let bytes = 0x1234567890123456isize.to_ne_bytes();
assert_eq!(
bytes,
if cfg!(target_endian = "big") {
[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]
} else {
[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]
}
);
```

RunCreate an integer value from its representation as a byte array in big endian.

**Note**: This function returns an array of length 2, 4 or 8 bytes
depending on the target pointer size.

##### Examples

```
let value = isize::from_be_bytes([0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]);
assert_eq!(value, 0x1234567890123456);
```

RunWhen starting from a slice rather than an array, fallible conversion APIs can be used:

```
use std::convert::TryInto;
fn read_be_isize(input: &mut &[u8]) -> isize {
let (int_bytes, rest) = input.split_at(std::mem::size_of::<isize>());
*input = rest;
isize::from_be_bytes(int_bytes.try_into().unwrap())
}
```

RunCreate an integer value from its representation as a byte array in little endian.

**Note**: This function returns an array of length 2, 4 or 8 bytes
depending on the target pointer size.

##### Examples

```
let value = isize::from_le_bytes([0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]);
assert_eq!(value, 0x1234567890123456);
```

RunWhen starting from a slice rather than an array, fallible conversion APIs can be used:

```
use std::convert::TryInto;
fn read_le_isize(input: &mut &[u8]) -> isize {
let (int_bytes, rest) = input.split_at(std::mem::size_of::<isize>());
*input = rest;
isize::from_le_bytes(int_bytes.try_into().unwrap())
}
```

RunCreate an integer value from its memory representation as a byte array in native endianness.

As the target platform’s native endianness is used, portable code
likely wants to use `from_be_bytes`

or `from_le_bytes`

, as
appropriate instead.

**Note**: This function returns an array of length 2, 4 or 8 bytes
depending on the target pointer size.

##### Examples

```
let value = isize::from_ne_bytes(if cfg!(target_endian = "big") {
[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]
} else {
[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]
});
assert_eq!(value, 0x1234567890123456);
```

RunWhen starting from a slice rather than an array, fallible conversion APIs can be used:

```
use std::convert::TryInto;
fn read_ne_isize(input: &mut &[u8]) -> isize {
let (int_bytes, rest) = input.split_at(std::mem::size_of::<isize>());
*input = rest;
isize::from_ne_bytes(int_bytes.try_into().unwrap())
}
```

Run## 👎 Deprecating in a future Rust version: replaced by the `MIN`

associated constant on this type

replaced by the `MIN`

associated constant on this type

New code should prefer to use
`isize::MIN`

instead.

Returns the smallest value that can be represented by this integer type.

## 👎 Deprecating in a future Rust version: replaced by the `MAX`

associated constant on this type

replaced by the `MAX`

associated constant on this type

New code should prefer to use
`isize::MAX`

instead.

Returns the largest value that can be represented by this integer type.

## Trait Implementations

Performs the `+=`

operation. Read more

Performs the `+=`

operation. Read more

Performs the `&=`

operation. Read more

Performs the `&=`

operation. Read more

#### type Output = NonZeroIsize

#### type Output = NonZeroIsize

The resulting type after applying the `|`

operator.

Performs the `|`

operation. Read more

Performs the `|=`

operation. Read more

Performs the `|=`

operation. Read more

Performs the `^=`

operation. Read more

Performs the `^=`

operation. Read more

This operation rounds towards zero, truncating any fractional part of the exact result.

## Panics

This operation will panic if `other == 0`

or the division results in overflow.

Performs the `/=`

operation. Read more

Performs the `/=`

operation. Read more

Converts a `NonZeroIsize`

into an `isize`

#### type Err = ParseIntError

#### type Err = ParseIntError

The associated error which can be returned from parsing.

Performs the `*=`

operation. Read more

Performs the `*=`

operation. Read more

This method returns an ordering between `self`

and `other`

values if one exists. Read more

This method tests less than (for `self`

and `other`

) and is used by the `<`

operator. Read more

This method tests less than or equal to (for `self`

and `other`

) and is used by the `<=`

operator. Read more

This method tests greater than or equal to (for `self`

and `other`

) and is used by the `>=`

operator. Read more

This operation satisfies `n % d == n - (n / d) * d`

. The
result has the same sign as the left operand.

## Panics

This operation will panic if `other == 0`

or if `self / other`

results in overflow.

Performs the `%=`

operation. Read more

Performs the `%=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the value that would be obtained by taking the *successor*
of `self`

`count`

times. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the value that would be obtained by taking the *predecessor*
of `self`

`count`

times. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the value that would be obtained by taking the *successor*
of `self`

`count`

times. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the value that would be obtained by taking the *predecessor*
of `self`

`count`

times. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the number of *successor* steps required to get from `start`

to `end`

. Read more

Performs the `-=`

operation. Read more

Performs the `-=`

operation. Read more