# Primitive Type f32

1.0.0 ·
Expand description

A 32-bit floating-point type (specifically, the “binary32” type defined in IEEE 754-2008).

This type can represent a wide range of decimal numbers, like `3.5`, `27`, `-113.75`, `0.0078125`, `34359738368`, `0`, `-1`. So unlike integer types (such as `i32`), floating-point types can represent non-integer numbers, too.

However, being able to represent this wide range of numbers comes at the cost of precision: floats can only represent some of the real numbers and calculation with floats round to a nearby representable number. For example, `5.0` and `1.0` can be exactly represented as `f32`, but `1.0 / 5.0` results in `0.20000000298023223876953125` since `0.2` cannot be exactly represented as `f32`. Note, however, that printing floats with `println` and friends will often discard insignificant digits: `println!("{}", 1.0f32 / 5.0f32)` will print `0.2`.

Additionally, `f32` can represent some special values:

• −0.0: IEEE 754 floating-point numbers have a bit that indicates their sign, so −0.0 is a possible value. For comparison −0.0 = +0.0, but floating-point operations can carry the sign bit through arithmetic operations. This means −0.0 × +0.0 produces −0.0 and a negative number rounded to a value smaller than a float can represent also produces −0.0.
• and −∞: these result from calculations like `1.0 / 0.0`.
• NaN (not a number): this value results from calculations like `(-1.0).sqrt()`. NaN has some potentially unexpected behavior:
• It is not equal to any float, including itself! This is the reason `f32` doesn’t implement the `Eq` trait.
• It is also neither smaller nor greater than any float, making it impossible to sort by the default comparison operation, which is the reason `f32` doesn’t implement the `Ord` trait.
• It is also considered infectious as almost all calculations where one of the operands is NaN will also result in NaN. The explanations on this page only explicitly document behavior on NaN operands if this default is deviated from.
• Lastly, there are multiple bit patterns that are considered NaN. Rust does not currently guarantee that the bit patterns of NaN are preserved over arithmetic operations, and they are not guaranteed to be portable or even fully deterministic! This means that there may be some surprising results upon inspecting the bit patterns, as the same calculations might produce NaNs with different bit patterns. This also affects the sign of the NaN: checking `is_sign_positive` or `is_sign_negative` on a NaN is the most common way to run into these surprising results. (Checking `x >= 0.0` or `x <= 0.0` avoids those surprises, but also how negative/positive zero are treated.) See the section below for what exactly is guaranteed about the bit pattern of a NaN.

When a primitive operation (addition, subtraction, multiplication, or division) is performed on this type, the result is rounded according to the roundTiesToEven direction defined in IEEE 754-2008. That means:

• The result is the representable value closest to the true value, if there is a unique closest representable value.
• If the true value is exactly half-way between two representable values, the result is the one with an even least-significant binary digit.
• If the true value’s magnitude is ≥ `f32::MAX` + 2(`f32::MAX_EXP``f32::MANTISSA_DIGITS` − 1), the result is ∞ or −∞ (preserving the true value’s sign).
• If the result of a sum exactly equals zero, the outcome is +0.0 unless both arguments were negative, then it is -0.0. Subtraction `a - b` is regarded as a sum `a + (-b)`.

See also the `std::f32::consts` module.

## §NaN bit patterns

This section defines the possible NaN bit patterns returned by floating-point operations.

The bit pattern of a floating-point NaN value is defined by:

• a sign bit.
• a quiet/signaling bit. Rust assumes that the quiet/signaling bit being set to `1` indicates a quiet NaN (QNaN), and a value of `0` indicates a signaling NaN (SNaN). In the following we will hence just call it the “quiet bit”.
• a payload, which makes up the rest of the significand (i.e., the mantissa) except for the quiet bit.

The rules for NaN values differ between arithmetic and non-arithmetic (or “bitwise”) operations. The non-arithmetic operations are unary `-`, `abs`, `copysign`, `signum`, `{to,from}_bits`, `{to,from}_{be,le,ne}_bytes` and `is_sign_{positive,negative}`. These operations are guaranteed to exactly preserve the bit pattern of their input except for possibly changing the sign bit.

The following rules apply when a NaN value is returned from an arithmetic operation:

• The result has a non-deterministic sign.

• The quiet bit and payload are non-deterministically chosen from the following set of options:

• Preferred NaN: The quiet bit is set and the payload is all-zero.
• Quieting NaN propagation: The quiet bit is set and the payload is copied from any input operand that is a NaN. If the inputs and outputs do not have the same payload size (i.e., for `as` casts), then
• If the output is smaller than the input, low-order bits of the payload get dropped.
• If the output is larger than the input, the payload gets filled up with 0s in the low-order bits.
• Unchanged NaN propagation: The quiet bit and payload are copied from any input operand that is a NaN. If the inputs and outputs do not have the same size (i.e., for `as` casts), the same rules as for “quieting NaN propagation” apply, with one caveat: if the output is smaller than the input, droppig the low-order bits may result in a payload of 0; a payload of 0 is not possible with a signaling NaN (the all-0 significand encodes an infinity) so unchanged NaN propagation cannot occur with some inputs.
• Target-specific NaN: The quiet bit is set and the payload is picked from a target-specific set of “extra” possible NaN payloads. The set can depend on the input operand values. See the table below for the concrete NaNs this set contains on various targets.

In particular, if all input NaNs are quiet (or if there are no input NaNs), then the output NaN is definitely quiet. Signaling NaN outputs can only occur if they are provided as an input value. Similarly, if all input NaNs are preferred (or if there are no input NaNs) and the target does not have any “extra” NaN payloads, then the output NaN is guaranteed to be preferred.

The non-deterministic choice happens when the operation is executed; i.e., the result of a NaN-producing floating-point operation is a stable bit pattern (looking at these bits multiple times will yield consistent results), but running the same operation twice with the same inputs can produce different results.

These guarantees are neither stronger nor weaker than those of IEEE 754: IEEE 754 guarantees that an operation never returns a signaling NaN, whereas it is possible for operations like `SNAN * 1.0` to return a signaling NaN in Rust. Conversely, IEEE 754 makes no statement at all about which quiet NaN is returned, whereas Rust restricts the set of possible results to the ones listed above.

Unless noted otherwise, the same rules also apply to NaNs returned by other library functions (e.g. `min`, `minimum`, `max`, `maximum`); other aspects of their semantics and which IEEE 754 operation they correspond to are documented with the respective functions.

When an arithmetic floating-point operation is executed in `const` context, the same rules apply: no guarantee is made about which of the NaN bit patterns described above will be returned. The result does not have to match what happens when executing the same code at runtime, and the result can vary depending on factors such as compiler version and flags.

#### §Target-specific “extra” NaN values

`target_arch`Extra payloads possible on this platform
`x86`, `x86_64`, `arm`, `aarch64`, `riscv32`, `riscv64`None
`sparc`, `sparc64`The all-one payload
`wasm32`, `wasm64`If all input NaNs are quiet with all-zero payload: None.

For targets not in this table, all payloads are possible.

## Implementations§

source§

### impl f32

1.43.0 · source

#### pub const RADIX: u32 = 2u32

The radix or base of the internal representation of `f32`.

1.43.0 · source

#### pub const MANTISSA_DIGITS: u32 = 24u32

Number of significant digits in base 2.

1.43.0 · source

#### pub const DIGITS: u32 = 6u32

Approximate number of significant digits in base 10.

This is the maximum x such that any decimal number with x significant digits can be converted to `f32` and back without loss.

Equal to floor(log10 2`MANTISSA_DIGITS` − 1).

1.43.0 · source

#### pub const EPSILON: f32 = 1.1920929E-7f32

Machine epsilon value for `f32`.

This is the difference between `1.0` and the next larger representable number.

Equal to 21 − `MANTISSA_DIGITS`.

1.43.0 · source

#### pub const MIN: f32 = -3.40282347E+38f32

Smallest finite `f32` value.

Equal to −`MAX`.

1.43.0 · source

#### pub const MIN_POSITIVE: f32 = 1.17549435E-38f32

Smallest positive normal `f32` value.

Equal to 2`MIN_EXP` − 1.

1.43.0 · source

#### pub const MAX: f32 = 3.40282347E+38f32

Largest finite `f32` value.

Equal to (1 − 2`MANTISSA_DIGITS`) 2`MAX_EXP`.

1.43.0 · source

#### pub const MIN_EXP: i32 = -125i32

One greater than the minimum possible normal power of 2 exponent.

If x = `MIN_EXP`, then normal numbers ≥ 0.5 × 2x.

1.43.0 · source

#### pub const MAX_EXP: i32 = 128i32

Maximum possible power of 2 exponent.

If x = `MAX_EXP`, then normal numbers < 1 × 2x.

1.43.0 · source

#### pub const MIN_10_EXP: i32 = -37i32

Minimum x for which 10x is normal.

Equal to ceil(log10 `MIN_POSITIVE`).

1.43.0 · source

#### pub const MAX_10_EXP: i32 = 38i32

Maximum x for which 10x is normal.

Equal to floor(log10 `MAX`).

1.43.0 · source

#### pub const NAN: f32 = NaN_f32

Not a Number (NaN).

Note that IEEE 754 doesn’t define just a single NaN value; a plethora of bit patterns are considered to be NaN. Furthermore, the standard makes a difference between a “signaling” and a “quiet” NaN, and allows inspecting its “payload” (the unspecified bits in the bit pattern). This constant isn’t guaranteed to equal to any specific NaN bitpattern, and the stability of its representation over Rust versions and target platforms isn’t guaranteed.

1.43.0 · source

Infinity (∞).

1.43.0 · source

#### pub const NEG_INFINITY: f32 = -Inf_f32

Negative infinity (−∞).

1.0.0 (const: unstable) · source

#### pub fn is_nan(self) -> bool

Returns `true` if this value is NaN.

``````let nan = f32::NAN;
let f = 7.0_f32;

assert!(nan.is_nan());
assert!(!f.is_nan());``````
1.0.0 (const: unstable) · source

#### pub fn is_infinite(self) -> bool

Returns `true` if this value is positive infinity or negative infinity, and `false` otherwise.

``````let f = 7.0f32;
let inf = f32::INFINITY;
let neg_inf = f32::NEG_INFINITY;
let nan = f32::NAN;

assert!(!f.is_infinite());
assert!(!nan.is_infinite());

assert!(inf.is_infinite());
assert!(neg_inf.is_infinite());``````
1.0.0 (const: unstable) · source

#### pub fn is_finite(self) -> bool

Returns `true` if this number is neither infinite nor NaN.

``````let f = 7.0f32;
let inf = f32::INFINITY;
let neg_inf = f32::NEG_INFINITY;
let nan = f32::NAN;

assert!(f.is_finite());

assert!(!nan.is_finite());
assert!(!inf.is_finite());
assert!(!neg_inf.is_finite());``````
1.53.0 (const: unstable) · source

#### pub fn is_subnormal(self) -> bool

Returns `true` if the number is subnormal.

``````let min = f32::MIN_POSITIVE; // 1.17549435e-38f32
let max = f32::MAX;
let lower_than_min = 1.0e-40_f32;
let zero = 0.0_f32;

assert!(!min.is_subnormal());
assert!(!max.is_subnormal());

assert!(!zero.is_subnormal());
assert!(!f32::NAN.is_subnormal());
assert!(!f32::INFINITY.is_subnormal());
// Values between `0` and `min` are Subnormal.
assert!(lower_than_min.is_subnormal());``````
1.0.0 (const: unstable) · source

#### pub fn is_normal(self) -> bool

Returns `true` if the number is neither zero, infinite, subnormal, or NaN.

``````let min = f32::MIN_POSITIVE; // 1.17549435e-38f32
let max = f32::MAX;
let lower_than_min = 1.0e-40_f32;
let zero = 0.0_f32;

assert!(min.is_normal());
assert!(max.is_normal());

assert!(!zero.is_normal());
assert!(!f32::NAN.is_normal());
assert!(!f32::INFINITY.is_normal());
// Values between `0` and `min` are Subnormal.
assert!(!lower_than_min.is_normal());``````
1.0.0 (const: unstable) · source

#### pub fn classify(self) -> FpCategory

Returns the floating point category of the number. If only one property is going to be tested, it is generally faster to use the specific predicate instead.

``````use std::num::FpCategory;

let num = 12.4_f32;
let inf = f32::INFINITY;

assert_eq!(num.classify(), FpCategory::Normal);
assert_eq!(inf.classify(), FpCategory::Infinite);``````
1.0.0 (const: unstable) · source

#### pub fn is_sign_positive(self) -> bool

Returns `true` if `self` has a positive sign, including `+0.0`, NaNs with positive sign bit and positive infinity.

Note that IEEE 754 doesn’t assign any meaning to the sign bit in case of a NaN, and as Rust doesn’t guarantee that the bit pattern of NaNs are conserved over arithmetic operations, the result of `is_sign_positive` on a NaN might produce an unexpected or non-portable result. See the specification of NaN bit patterns for more info. Use `self.signum() == 1.0` if you need fully portable behavior (will return `false` for all NaNs).

``````let f = 7.0_f32;
let g = -7.0_f32;

assert!(f.is_sign_positive());
assert!(!g.is_sign_positive());``````
1.0.0 (const: unstable) · source

#### pub fn is_sign_negative(self) -> bool

Returns `true` if `self` has a negative sign, including `-0.0`, NaNs with negative sign bit and negative infinity.

Note that IEEE 754 doesn’t assign any meaning to the sign bit in case of a NaN, and as Rust doesn’t guarantee that the bit pattern of NaNs are conserved over arithmetic operations, the result of `is_sign_negative` on a NaN might produce an unexpected or non-portable result. See the specification of NaN bit patterns for more info. Use `self.signum() == -1.0` if you need fully portable behavior (will return `false` for all NaNs).

``````let f = 7.0f32;
let g = -7.0f32;

assert!(!f.is_sign_negative());
assert!(g.is_sign_negative());``````
source

#### pub const fn next_up(self) -> Self

🔬This is a nightly-only experimental API. (`float_next_up_down` #91399)

Returns the least number greater than `self`.

Let `TINY` be the smallest representable positive `f32`. Then,

The identity `x.next_up() == -(-x).next_down()` holds for all non-NaN `x`. When `x` is finite `x == x.next_up().next_down()` also holds.

``````#![feature(float_next_up_down)]
// f32::EPSILON is the difference between 1.0 and the next number up.
assert_eq!(1.0f32.next_up(), 1.0 + f32::EPSILON);
// But not for most numbers.
assert!(0.1f32.next_up() < 0.1 + f32::EPSILON);
assert_eq!(16777216f32.next_up(), 16777218.0);``````
source

#### pub const fn next_down(self) -> Self

🔬This is a nightly-only experimental API. (`float_next_up_down` #91399)

Returns the greatest number less than `self`.

Let `TINY` be the smallest representable positive `f32`. Then,

The identity `x.next_down() == -(-x).next_up()` holds for all non-NaN `x`. When `x` is finite `x == x.next_down().next_up()` also holds.

``````#![feature(float_next_up_down)]
let x = 1.0f32;
// Clamp value into range [0, 1).
let clamped = x.clamp(0.0, 1.0f32.next_down());
assert!(clamped < 1.0);
assert_eq!(clamped.next_up(), 1.0);``````
1.0.0 · source

#### pub fn recip(self) -> f32

Takes the reciprocal (inverse) of a number, `1/x`.

``````let x = 2.0_f32;
let abs_difference = (x.recip() - (1.0 / x)).abs();

assert!(abs_difference <= f32::EPSILON);``````
1.7.0 · source

#### pub fn to_degrees(self) -> f32

``````let angle = std::f32::consts::PI;

let abs_difference = (angle.to_degrees() - 180.0).abs();
assert!(abs_difference <= f32::EPSILON);``````
1.7.0 · source

#### pub fn to_radians(self) -> f32

``````let angle = 180.0f32;

let abs_difference = (angle.to_radians() - std::f32::consts::PI).abs();

assert!(abs_difference <= f32::EPSILON);``````
1.0.0 · source

#### pub fn max(self, other: f32) -> f32

Returns the maximum of the two numbers, ignoring NaN.

If one of the arguments is NaN, then the other argument is returned. This follows the IEEE 754-2008 semantics for maxNum, except for handling of signaling NaNs; this function handles all NaNs the same way and avoids maxNum’s problems with associativity. This also matches the behavior of libm’s fmax.

``````let x = 1.0f32;
let y = 2.0f32;

assert_eq!(x.max(y), y);``````
1.0.0 · source

#### pub fn min(self, other: f32) -> f32

Returns the minimum of the two numbers, ignoring NaN.

If one of the arguments is NaN, then the other argument is returned. This follows the IEEE 754-2008 semantics for minNum, except for handling of signaling NaNs; this function handles all NaNs the same way and avoids minNum’s problems with associativity. This also matches the behavior of libm’s fmin.

``````let x = 1.0f32;
let y = 2.0f32;

assert_eq!(x.min(y), x);``````
source

#### pub fn maximum(self, other: f32) -> f32

🔬This is a nightly-only experimental API. (`float_minimum_maximum` #91079)

Returns the maximum of the two numbers, propagating NaN.

This returns NaN when either argument is NaN, as opposed to `f32::max` which only returns NaN when both arguments are NaN.

``````#![feature(float_minimum_maximum)]
let x = 1.0f32;
let y = 2.0f32;

assert_eq!(x.maximum(y), y);
assert!(x.maximum(f32::NAN).is_nan());``````

If one of the arguments is NaN, then NaN is returned. Otherwise this returns the greater of the two numbers. For this operation, -0.0 is considered to be less than +0.0. Note that this follows the semantics specified in IEEE 754-2019.

Also note that “propagation” of NaNs here doesn’t necessarily mean that the bitpattern of a NaN operand is conserved; see the specification of NaN bit patterns for more info.

source

#### pub fn minimum(self, other: f32) -> f32

🔬This is a nightly-only experimental API. (`float_minimum_maximum` #91079)

Returns the minimum of the two numbers, propagating NaN.

This returns NaN when either argument is NaN, as opposed to `f32::min` which only returns NaN when both arguments are NaN.

``````#![feature(float_minimum_maximum)]
let x = 1.0f32;
let y = 2.0f32;

assert_eq!(x.minimum(y), x);
assert!(x.minimum(f32::NAN).is_nan());``````

If one of the arguments is NaN, then NaN is returned. Otherwise this returns the lesser of the two numbers. For this operation, -0.0 is considered to be less than +0.0. Note that this follows the semantics specified in IEEE 754-2019.

Also note that “propagation” of NaNs here doesn’t necessarily mean that the bitpattern of a NaN operand is conserved; see the specification of NaN bit patterns for more info.

source

#### pub fn midpoint(self, other: f32) -> f32

🔬This is a nightly-only experimental API. (`num_midpoint` #110840)

Calculates the middle point of `self` and `rhs`.

This returns NaN when either argument is NaN or if a combination of +inf and -inf is provided as arguments.

##### §Examples
``````#![feature(num_midpoint)]
assert_eq!(1f32.midpoint(4.0), 2.5);
assert_eq!((-5.5f32).midpoint(8.0), 1.25);``````
1.44.0 · source

#### pub unsafe fn to_int_unchecked<Int>(self) -> Intwhere Self: FloatToInt<Int>,

Rounds toward zero and converts to any primitive integer type, assuming that the value is finite and fits in that type.

``````let value = 4.6_f32;
let rounded = unsafe { value.to_int_unchecked::<u16>() };
assert_eq!(rounded, 4);

let value = -128.9_f32;
let rounded = unsafe { value.to_int_unchecked::<i8>() };
assert_eq!(rounded, i8::MIN);``````
##### §Safety

The value must:

• Not be `NaN`
• Not be infinite
• Be representable in the return type `Int`, after truncating off its fractional part
1.20.0 (const: unstable) · source

#### pub fn to_bits(self) -> u32

Raw transmutation to `u32`.

This is currently identical to `transmute::<f32, u32>(self)` on all platforms.

See `from_bits` for some discussion of the portability of this operation (there are almost no issues).

Note that this function is distinct from `as` casting, which attempts to preserve the numeric value, and not the bitwise value.

##### §Examples
``````assert_ne!((1f32).to_bits(), 1f32 as u32); // to_bits() is not casting!
assert_eq!((12.5f32).to_bits(), 0x41480000);
``````
1.20.0 (const: unstable) · source

#### pub fn from_bits(v: u32) -> Self

Raw transmutation from `u32`.

This is currently identical to `transmute::<u32, f32>(v)` on all platforms. It turns out this is incredibly portable, for two reasons:

• Floats and Ints have the same endianness on all supported platforms.
• IEEE 754 very precisely specifies the bit layout of floats.

However there is one caveat: prior to the 2008 version of IEEE 754, how to interpret the NaN signaling bit wasn’t actually specified. Most platforms (notably x86 and ARM) picked the interpretation that was ultimately standardized in 2008, but some didn’t (notably MIPS). As a result, all signaling NaNs on MIPS are quiet NaNs on x86, and vice-versa.

Rather than trying to preserve signaling-ness cross-platform, this implementation favors preserving the exact bits. This means that any payloads encoded in NaNs will be preserved even if the result of this method is sent over the network from an x86 machine to a MIPS one.

If the results of this method are only manipulated by the same architecture that produced them, then there is no portability concern.

If the input isn’t NaN, then there is no portability concern.

If you don’t care about signalingness (very likely), then there is no portability concern.

Note that this function is distinct from `as` casting, which attempts to preserve the numeric value, and not the bitwise value.

##### §Examples
``````let v = f32::from_bits(0x41480000);
assert_eq!(v, 12.5);``````
1.40.0 (const: unstable) · source

#### pub fn to_be_bytes(self) -> [u8; 4]

Returns the memory representation of this floating point number as a byte array in big-endian (network) byte order.

See `from_bits` for some discussion of the portability of this operation (there are almost no issues).

##### §Examples
``````let bytes = 12.5f32.to_be_bytes();
assert_eq!(bytes, [0x41, 0x48, 0x00, 0x00]);``````
1.40.0 (const: unstable) · source

#### pub fn to_le_bytes(self) -> [u8; 4]

Returns the memory representation of this floating point number as a byte array in little-endian byte order.

See `from_bits` for some discussion of the portability of this operation (there are almost no issues).

##### §Examples
``````let bytes = 12.5f32.to_le_bytes();
assert_eq!(bytes, [0x00, 0x00, 0x48, 0x41]);``````
1.40.0 (const: unstable) · source

#### pub fn to_ne_bytes(self) -> [u8; 4]

Returns the memory representation of this floating point number 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.

See `from_bits` for some discussion of the portability of this operation (there are almost no issues).

##### §Examples
``````let bytes = 12.5f32.to_ne_bytes();
assert_eq!(
bytes,
if cfg!(target_endian = "big") {
[0x41, 0x48, 0x00, 0x00]
} else {
[0x00, 0x00, 0x48, 0x41]
}
);``````
1.40.0 (const: unstable) · source

#### pub fn from_be_bytes(bytes: [u8; 4]) -> Self

Creates a floating point value from its representation as a byte array in big endian.

See `from_bits` for some discussion of the portability of this operation (there are almost no issues).

##### §Examples
``````let value = f32::from_be_bytes([0x41, 0x48, 0x00, 0x00]);
assert_eq!(value, 12.5);``````
1.40.0 (const: unstable) · source

#### pub fn from_le_bytes(bytes: [u8; 4]) -> Self

Creates a floating point value from its representation as a byte array in little endian.

See `from_bits` for some discussion of the portability of this operation (there are almost no issues).

##### §Examples
``````let value = f32::from_le_bytes([0x00, 0x00, 0x48, 0x41]);
assert_eq!(value, 12.5);``````
1.40.0 (const: unstable) · source

#### pub fn from_ne_bytes(bytes: [u8; 4]) -> Self

Creates a floating point value from its representation as a byte array in native endian.

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.

See `from_bits` for some discussion of the portability of this operation (there are almost no issues).

##### §Examples
``````let value = f32::from_ne_bytes(if cfg!(target_endian = "big") {
[0x41, 0x48, 0x00, 0x00]
} else {
[0x00, 0x00, 0x48, 0x41]
});
assert_eq!(value, 12.5);``````
1.62.0 · source

#### pub fn total_cmp(&self, other: &Self) -> Ordering

Returns the ordering between `self` and `other`.

Unlike the standard partial comparison between floating point numbers, this comparison always produces an ordering in accordance to the `totalOrder` predicate as defined in the IEEE 754 (2008 revision) floating point standard. The values are ordered in the following sequence:

• negative quiet NaN
• negative signaling NaN
• negative infinity
• negative numbers
• negative subnormal numbers
• negative zero
• positive zero
• positive subnormal numbers
• positive numbers
• positive infinity
• positive signaling NaN
• positive quiet NaN.

The ordering established by this function does not always agree with the `PartialOrd` and `PartialEq` implementations of `f32`. For example, they consider negative and positive zero equal, while `total_cmp` doesn’t.

The interpretation of the signaling NaN bit follows the definition in the IEEE 754 standard, which may not match the interpretation by some of the older, non-conformant (e.g. MIPS) hardware implementations.

##### §Example
``````struct GoodBoy {
name: String,
weight: f32,
}

let mut bois = vec![
GoodBoy { name: "Pucci".to_owned(), weight: 0.1 },
GoodBoy { name: "Woofer".to_owned(), weight: 99.0 },
GoodBoy { name: "Yapper".to_owned(), weight: 10.0 },
GoodBoy { name: "Chonk".to_owned(), weight: f32::INFINITY },
GoodBoy { name: "Abs. Unit".to_owned(), weight: f32::NAN },
GoodBoy { name: "Floaty".to_owned(), weight: -5.0 },
];

bois.sort_by(|a, b| a.weight.total_cmp(&b.weight));

// `f32::NAN` could be positive or negative, which will affect the sort order.
if f32::NAN.is_sign_negative() {
assert!(bois.into_iter().map(|b| b.weight)
.zip([f32::NAN, -5.0, 0.1, 10.0, 99.0, f32::INFINITY].iter())
.all(|(a, b)| a.to_bits() == b.to_bits()))
} else {
assert!(bois.into_iter().map(|b| b.weight)
.zip([-5.0, 0.1, 10.0, 99.0, f32::INFINITY, f32::NAN].iter())
.all(|(a, b)| a.to_bits() == b.to_bits()))
}``````
1.50.0 · source

#### pub fn clamp(self, min: f32, max: f32) -> f32

Restrict a value to a certain interval unless it is NaN.

Returns `max` if `self` is greater than `max`, and `min` if `self` is less than `min`. Otherwise this returns `self`.

Note that this function returns NaN if the initial value was NaN as well.

##### §Panics

Panics if `min > max`, `min` is NaN, or `max` is NaN.

##### §Examples
``````assert!((-3.0f32).clamp(-2.0, 1.0) == -2.0);
assert!((0.0f32).clamp(-2.0, 1.0) == 0.0);
assert!((2.0f32).clamp(-2.0, 1.0) == 1.0);
assert!((f32::NAN).clamp(-2.0, 1.0).is_nan());``````

## Trait Implementations§

1.0.0 · source§

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#### type Output = <f32 as Add>::Output

The resulting type after applying the `+` operator.
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Performs the `+` operation. Read more
1.0.0 · source§

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#### type Output = <f32 as Add>::Output

The resulting type after applying the `+` operator.
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Performs the `+` operation. Read more
1.0.0 · source§

### impl<'a> Add<f32> for &'a f32

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#### type Output = <f32 as Add>::Output

The resulting type after applying the `+` operator.
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Performs the `+` operation. Read more
1.0.0 · source§

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#### type Output = f32

The resulting type after applying the `+` operator.
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#### fn add(self, other: f32) -> f32

Performs the `+` operation. Read more
1.22.0 · source§

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#### fn add_assign(&mut self, other: &f32)

Performs the `+=` operation. Read more
1.8.0 · source§

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#### fn add_assign(&mut self, other: f32)

Performs the `+=` operation. Read more
1.0.0 · source§

### impl Clone for f32

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#### fn clone(&self) -> Self

Returns a copy of the value. Read more
1.0.0 · source§

#### fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more
1.0.0 · source§

### impl Debug for f32

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#### fn fmt(&self, fmt: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
1.0.0 · source§

### impl Default for f32

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#### fn default() -> f32

Returns the default value of `0.0`

1.0.0 · source§

### impl Display for f32

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#### fn fmt(&self, fmt: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
1.0.0 · source§

### impl Div<&f32> for &f32

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#### type Output = <f32 as Div>::Output

The resulting type after applying the `/` operator.
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#### fn div(self, other: &f32) -> <f32 as Div<f32>>::Output

Performs the `/` operation. Read more
1.0.0 · source§

### impl Div<&f32> for f32

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#### type Output = <f32 as Div>::Output

The resulting type after applying the `/` operator.
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#### fn div(self, other: &f32) -> <f32 as Div<f32>>::Output

Performs the `/` operation. Read more
1.0.0 · source§

### impl<'a> Div<f32> for &'a f32

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#### type Output = <f32 as Div>::Output

The resulting type after applying the `/` operator.
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#### fn div(self, other: f32) -> <f32 as Div<f32>>::Output

Performs the `/` operation. Read more
1.0.0 · source§

### impl Div for f32

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#### type Output = f32

The resulting type after applying the `/` operator.
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#### fn div(self, other: f32) -> f32

Performs the `/` operation. Read more
1.22.0 · source§

### impl DivAssign<&f32> for f32

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#### fn div_assign(&mut self, other: &f32)

Performs the `/=` operation. Read more
1.8.0 · source§

### impl DivAssign for f32

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#### fn div_assign(&mut self, other: f32)

Performs the `/=` operation. Read more
1.68.0 · source§

### impl From<bool> for f32

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#### fn from(small: bool) -> Self

Converts a `bool` to `f32` losslessly. The resulting value is positive `0.0` for `false` and `1.0` for `true` values.

##### §Examples
``````let x: f32 = false.into();
assert_eq!(x, 0.0);
assert!(x.is_sign_positive());

let y: f32 = true.into();
assert_eq!(y, 1.0);``````
1.6.0 · source§

### impl From<f32> for f128

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#### fn from(small: f32) -> Self

Converts `f32` to `f128` losslessly.

1.6.0 · source§

### impl From<f32> for f64

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#### fn from(small: f32) -> Self

Converts `f32` to `f64` losslessly.

1.6.0 · source§

### impl From<i16> for f32

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#### fn from(small: i16) -> Self

Converts `i16` to `f32` losslessly.

1.6.0 · source§

### impl From<i8> for f32

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#### fn from(small: i8) -> Self

Converts `i8` to `f32` losslessly.

1.6.0 · source§

### impl From<u16> for f32

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#### fn from(small: u16) -> Self

Converts `u16` to `f32` losslessly.

1.6.0 · source§

### impl From<u8> for f32

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#### fn from(small: u8) -> Self

Converts `u8` to `f32` losslessly.

1.0.0 · source§

### impl FromStr for f32

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#### fn from_str(src: &str) -> Result<Self, ParseFloatError>

Converts a string in base 10 to a float. Accepts an optional decimal exponent.

This function accepts strings such as

• ‘3.14’
• ‘-3.14’
• ‘2.5E10’, or equivalently, ‘2.5e10’
• ‘2.5E-10’
• ‘5.’
• ‘.5’, or, equivalently, ‘0.5’
• ‘inf’, ‘-inf’, ‘+infinity’, ‘NaN’

Note that alphabetical characters are not case-sensitive.

Leading and trailing whitespace represent an error.

##### §Grammar

All strings that adhere to the following EBNF grammar when lowercased will result in an `Ok` being returned:

``````Float  ::= Sign? ( 'inf' | 'infinity' | 'nan' | Number )
Number ::= ( Digit+ |
Digit+ '.' Digit* |
Digit* '.' Digit+ ) Exp?
Exp    ::= 'e' Sign? Digit+
Sign   ::= [+-]
Digit  ::= [0-9]
``````
##### §Arguments
• src - A string
##### §Return value

`Err(ParseFloatError)` if the string did not represent a valid number. Otherwise, `Ok(n)` where `n` is the closest representable floating-point number to the number represented by `src` (following the same rules for rounding as for the results of primitive operations).

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#### type Err = ParseFloatError

The associated error which can be returned from parsing.
1.0.0 · source§

### impl LowerExp for f32

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#### fn fmt(&self, fmt: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
1.0.0 · source§

### impl Mul<&f32> for &f32

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#### type Output = <f32 as Mul>::Output

The resulting type after applying the `*` operator.
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#### fn mul(self, other: &f32) -> <f32 as Mul<f32>>::Output

Performs the `*` operation. Read more
1.0.0 · source§

### impl Mul<&f32> for f32

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#### type Output = <f32 as Mul>::Output

The resulting type after applying the `*` operator.
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#### fn mul(self, other: &f32) -> <f32 as Mul<f32>>::Output

Performs the `*` operation. Read more
1.0.0 · source§

### impl<'a> Mul<f32> for &'a f32

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#### type Output = <f32 as Mul>::Output

The resulting type after applying the `*` operator.
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#### fn mul(self, other: f32) -> <f32 as Mul<f32>>::Output

Performs the `*` operation. Read more
1.0.0 · source§

### impl Mul for f32

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#### type Output = f32

The resulting type after applying the `*` operator.
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#### fn mul(self, other: f32) -> f32

Performs the `*` operation. Read more
1.22.0 · source§

### impl MulAssign<&f32> for f32

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#### fn mul_assign(&mut self, other: &f32)

Performs the `*=` operation. Read more
1.8.0 · source§

### impl MulAssign for f32

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#### fn mul_assign(&mut self, other: f32)

Performs the `*=` operation. Read more
1.0.0 · source§

### impl Neg for &f32

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#### type Output = <f32 as Neg>::Output

The resulting type after applying the `-` operator.
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#### fn neg(self) -> <f32 as Neg>::Output

Performs the unary `-` operation. Read more
1.0.0 · source§

### impl Neg for f32

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#### type Output = f32

The resulting type after applying the `-` operator.
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#### fn neg(self) -> f32

Performs the unary `-` operation. Read more
1.0.0 · source§

### impl PartialEq for f32

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#### fn eq(&self, other: &f32) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
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#### fn ne(&self, other: &f32) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 · source§

### impl PartialOrd for f32

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#### fn partial_cmp(&self, other: &f32) -> Option<Ordering>

This method returns an ordering between `self` and `other` values if one exists. Read more
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#### fn lt(&self, other: &f32) -> bool

Tests less than (for `self` and `other`) and is used by the `<` operator. Read more
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#### fn le(&self, other: &f32) -> bool

Tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more
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#### fn ge(&self, other: &f32) -> bool

Tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more
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#### fn gt(&self, other: &f32) -> bool

Tests greater than (for `self` and `other`) and is used by the `>` operator. Read more
1.12.0 · source§

### impl<'a> Product<&'a f32> for f32

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#### fn product<I: Iterator<Item = &'a Self>>(iter: I) -> Self

Takes an iterator and generates `Self` from the elements by multiplying the items.
1.12.0 · source§

### impl Product for f32

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#### fn product<I: Iterator<Item = Self>>(iter: I) -> Self

Takes an iterator and generates `Self` from the elements by multiplying the items.
1.0.0 · source§

### impl Rem<&f32> for &f32

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#### type Output = <f32 as Rem>::Output

The resulting type after applying the `%` operator.
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#### fn rem(self, other: &f32) -> <f32 as Rem<f32>>::Output

Performs the `%` operation. Read more
1.0.0 · source§

### impl Rem<&f32> for f32

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#### type Output = <f32 as Rem>::Output

The resulting type after applying the `%` operator.
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#### fn rem(self, other: &f32) -> <f32 as Rem<f32>>::Output

Performs the `%` operation. Read more
1.0.0 · source§

### impl<'a> Rem<f32> for &'a f32

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#### type Output = <f32 as Rem>::Output

The resulting type after applying the `%` operator.
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#### fn rem(self, other: f32) -> <f32 as Rem<f32>>::Output

Performs the `%` operation. Read more
1.0.0 · source§

### impl Rem for f32

The remainder from the division of two floats.

The remainder has the same sign as the dividend and is computed as: `x - (x / y).trunc() * y`.

#### §Examples

``````let x: f32 = 50.50;
let y: f32 = 8.125;
let remainder = x - (x / y).trunc() * y;

// The answer to both operations is 1.75
assert_eq!(x % y, remainder);``````
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#### type Output = f32

The resulting type after applying the `%` operator.
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#### fn rem(self, other: f32) -> f32

Performs the `%` operation. Read more
1.22.0 · source§

### impl RemAssign<&f32> for f32

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#### fn rem_assign(&mut self, other: &f32)

Performs the `%=` operation. Read more
1.8.0 · source§

### impl RemAssign for f32

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#### fn rem_assign(&mut self, other: f32)

Performs the `%=` operation. Read more
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### impl SimdElement for f32

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🔬This is a nightly-only experimental API. (`portable_simd` #86656)
The mask element type corresponding to this element type.
1.0.0 · source§

### impl Sub<&f32> for &f32

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#### type Output = <f32 as Sub>::Output

The resulting type after applying the `-` operator.
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#### fn sub(self, other: &f32) -> <f32 as Sub<f32>>::Output

Performs the `-` operation. Read more
1.0.0 · source§

### impl Sub<&f32> for f32

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#### type Output = <f32 as Sub>::Output

The resulting type after applying the `-` operator.
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#### fn sub(self, other: &f32) -> <f32 as Sub<f32>>::Output

Performs the `-` operation. Read more
1.0.0 · source§

### impl<'a> Sub<f32> for &'a f32

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#### type Output = <f32 as Sub>::Output

The resulting type after applying the `-` operator.
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#### fn sub(self, other: f32) -> <f32 as Sub<f32>>::Output

Performs the `-` operation. Read more
1.0.0 · source§

### impl Sub for f32

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#### type Output = f32

The resulting type after applying the `-` operator.
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#### fn sub(self, other: f32) -> f32

Performs the `-` operation. Read more
1.22.0 · source§

### impl SubAssign<&f32> for f32

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#### fn sub_assign(&mut self, other: &f32)

Performs the `-=` operation. Read more
1.8.0 · source§

### impl SubAssign for f32

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#### fn sub_assign(&mut self, other: f32)

Performs the `-=` operation. Read more
1.12.0 · source§

### impl<'a> Sum<&'a f32> for f32

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#### fn sum<I: Iterator<Item = &'a Self>>(iter: I) -> Self

Takes an iterator and generates `Self` from the elements by “summing up” the items.
1.12.0 · source§

### impl Sum for f32

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#### fn sum<I: Iterator<Item = Self>>(iter: I) -> Self

Takes an iterator and generates `Self` from the elements by “summing up” the items.
1.0.0 · source§

### impl UpperExp for f32

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#### fn fmt(&self, fmt: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
1.0.0 · source§

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## Blanket Implementations§

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### impl<T> Any for Twhere T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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### impl<T> Borrow<T> for Twhere T: ?Sized,

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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for Twhere T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<T> CloneToUninit for Twhere T: Clone,

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#### unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (`clone_to_uninit` #126799)
Performs copy-assignment from `self` to `dst`. Read more
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### impl<T> From<T> for T

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#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T, U> Into<U> for Twhere U: From<T>,

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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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### impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.