Struct ArgIntoFloat

pub struct ArgIntoFloat { /* private fields */ }

A Python float-like object.

ArgIntoFloat implements FromArgs so that a built-in function can accept any object that can be transformed into a float.

If the object is not a Python floating point object but has a __float__() method, this method will first be called to convert the object into a float. If __float__() is not defined then it falls back to __index__().

Implementations

impl ArgIntoFloat

pub fn vec_into_f64(v: Vec<Self>) -> Vec<f64>

Methods from Deref<Target = f64>

pub const RADIX: u32 = 2u32

pub const MANTISSA_DIGITS: u32 = 53u32

pub const DIGITS: u32 = 15u32

pub const EPSILON: f64 = 2.2204460492503131E-16f64

pub const MIN: f64 = -1.7976931348623157E+308f64

pub const MIN_POSITIVE: f64 = 2.2250738585072014E-308f64

pub const MAX: f64 = 1.7976931348623157E+308f64

pub const MIN_EXP: i32 = -1_021i32

pub const MAX_EXP: i32 = 1_024i32

pub const MIN_10_EXP: i32 = -307i32

pub const MAX_10_EXP: i32 = 308i32

pub const NAN: f64 = NaN_f64

pub const INFINITY: f64 = +Inf_f64

pub const NEG_INFINITY: f64 = -Inf_f64

pub fn total_cmp(&self, other: &f64) -> 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 f64. 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: f64,
}

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: f64::INFINITY },
    GoodBoy { name: "Abs. Unit".to_owned(), weight: f64::NAN },
    GoodBoy { name: "Floaty".to_owned(), weight: -5.0 },
];

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

// `f64::NAN` could be positive or negative, which will affect the sort order.
if f64::NAN.is_sign_negative() {
    assert!(bois.into_iter().map(|b| b.weight)
        .zip([f64::NAN, -5.0, 0.1, 10.0, 99.0, f64::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, f64::INFINITY, f64::NAN].iter())
        .all(|(a, b)| a.to_bits() == b.to_bits()))
}

Trait Implementations

impl Debug for ArgIntoFloat

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

Formats the value using the given formatter.

impl Deref for ArgIntoFloat

type Target = f64

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl From<ArgIntoFloat> for f64

fn from(arg: ArgIntoFloat) -> Self

Converts to this type from the input type.

impl PartialEq for ArgIntoFloat

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

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

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

impl TryFromObject for ArgIntoFloat

fn try_from_object(vm: &VirtualMachine, obj: PyObjectRef) -> PyResult<Self>

Attempt to convert a Python object to a value of this type.

impl StructuralPartialEq for ArgIntoFloat