Primitive Type f641.0.0 []

The 64-bit floating point type.

See also the std::f64 module.

Methods

impl f64
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Returns true if this value is NaN and false otherwise.

use std::f64;

let nan = f64::NAN;
let f = 7.0_f64;

assert!(nan.is_nan());
assert!(!f.is_nan());Run

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

use std::f64;

let f = 7.0f64;
let inf = f64::INFINITY;
let neg_inf = f64::NEG_INFINITY;
let nan = f64::NAN;

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

assert!(inf.is_infinite());
assert!(neg_inf.is_infinite());Run

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Returns true if this number is neither infinite nor NaN.

use std::f64;

let f = 7.0f64;
let inf: f64 = f64::INFINITY;
let neg_inf: f64 = f64::NEG_INFINITY;
let nan: f64 = f64::NAN;

assert!(f.is_finite());

assert!(!nan.is_finite());
assert!(!inf.is_finite());
assert!(!neg_inf.is_finite());Run

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

use std::f64;

let min = f64::MIN_POSITIVE; // 2.2250738585072014e-308f64
let max = f64::MAX;
let lower_than_min = 1.0e-308_f64;
let zero = 0.0f64;

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

assert!(!zero.is_normal());
assert!(!f64::NAN.is_normal());
assert!(!f64::INFINITY.is_normal());
// Values between `0` and `min` are Subnormal.
assert!(!lower_than_min.is_normal());Run

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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;
use std::f64;

let num = 12.4_f64;
let inf = f64::INFINITY;

assert_eq!(num.classify(), FpCategory::Normal);
assert_eq!(inf.classify(), FpCategory::Infinite);Run

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Returns the largest integer less than or equal to a number.

let f = 3.99_f64;
let g = 3.0_f64;

assert_eq!(f.floor(), 3.0);
assert_eq!(g.floor(), 3.0);Run

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Returns the smallest integer greater than or equal to a number.

let f = 3.01_f64;
let g = 4.0_f64;

assert_eq!(f.ceil(), 4.0);
assert_eq!(g.ceil(), 4.0);Run

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Returns the nearest integer to a number. Round half-way cases away from 0.0.

let f = 3.3_f64;
let g = -3.3_f64;

assert_eq!(f.round(), 3.0);
assert_eq!(g.round(), -3.0);Run

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Returns the integer part of a number.

let f = 3.3_f64;
let g = -3.7_f64;

assert_eq!(f.trunc(), 3.0);
assert_eq!(g.trunc(), -3.0);Run

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Returns the fractional part of a number.

let x = 3.5_f64;
let y = -3.5_f64;
let abs_difference_x = (x.fract() - 0.5).abs();
let abs_difference_y = (y.fract() - (-0.5)).abs();

assert!(abs_difference_x < 1e-10);
assert!(abs_difference_y < 1e-10);Run

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Computes the absolute value of self. Returns NAN if the number is NAN.

use std::f64;

let x = 3.5_f64;
let y = -3.5_f64;

let abs_difference_x = (x.abs() - x).abs();
let abs_difference_y = (y.abs() - (-y)).abs();

assert!(abs_difference_x < 1e-10);
assert!(abs_difference_y < 1e-10);

assert!(f64::NAN.abs().is_nan());Run

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Returns a number that represents the sign of self.

  • 1.0 if the number is positive, +0.0 or INFINITY
  • -1.0 if the number is negative, -0.0 or NEG_INFINITY
  • NAN if the number is NAN
use std::f64;

let f = 3.5_f64;

assert_eq!(f.signum(), 1.0);
assert_eq!(f64::NEG_INFINITY.signum(), -1.0);

assert!(f64::NAN.signum().is_nan());Run

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

let f = 7.0_f64;
let g = -7.0_f64;

assert!(f.is_sign_positive());
assert!(!g.is_sign_positive());Run

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Deprecated since 1.0.0

: renamed to is_sign_positive

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

let f = 7.0_f64;
let g = -7.0_f64;

assert!(!f.is_sign_negative());
assert!(g.is_sign_negative());Run

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Deprecated since 1.0.0

: renamed to is_sign_negative

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Fused multiply-add. Computes (self * a) + b with only one rounding error. This produces a more accurate result with better performance than a separate multiplication operation followed by an add.

let m = 10.0_f64;
let x = 4.0_f64;
let b = 60.0_f64;

// 100.0
let abs_difference = (m.mul_add(x, b) - (m*x + b)).abs();

assert!(abs_difference < 1e-10);Run

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

let x = 2.0_f64;
let abs_difference = (x.recip() - (1.0/x)).abs();

assert!(abs_difference < 1e-10);Run

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Raises a number to an integer power.

Using this function is generally faster than using powf

let x = 2.0_f64;
let abs_difference = (x.powi(2) - x*x).abs();

assert!(abs_difference < 1e-10);Run

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Raises a number to a floating point power.

let x = 2.0_f64;
let abs_difference = (x.powf(2.0) - x*x).abs();

assert!(abs_difference < 1e-10);Run

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Takes the square root of a number.

Returns NaN if self is a negative number.

let positive = 4.0_f64;
let negative = -4.0_f64;

let abs_difference = (positive.sqrt() - 2.0).abs();

assert!(abs_difference < 1e-10);
assert!(negative.sqrt().is_nan());Run

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Returns e^(self), (the exponential function).

let one = 1.0_f64;
// e^1
let e = one.exp();

// ln(e) - 1 == 0
let abs_difference = (e.ln() - 1.0).abs();

assert!(abs_difference < 1e-10);Run

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Returns 2^(self).

let f = 2.0_f64;

// 2^2 - 4 == 0
let abs_difference = (f.exp2() - 4.0).abs();

assert!(abs_difference < 1e-10);Run

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Returns the natural logarithm of the number.

let one = 1.0_f64;
// e^1
let e = one.exp();

// ln(e) - 1 == 0
let abs_difference = (e.ln() - 1.0).abs();

assert!(abs_difference < 1e-10);Run

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Returns the logarithm of the number with respect to an arbitrary base.

let ten = 10.0_f64;
let two = 2.0_f64;

// log10(10) - 1 == 0
let abs_difference_10 = (ten.log(10.0) - 1.0).abs();

// log2(2) - 1 == 0
let abs_difference_2 = (two.log(2.0) - 1.0).abs();

assert!(abs_difference_10 < 1e-10);
assert!(abs_difference_2 < 1e-10);Run

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Returns the base 2 logarithm of the number.

let two = 2.0_f64;

// log2(2) - 1 == 0
let abs_difference = (two.log2() - 1.0).abs();

assert!(abs_difference < 1e-10);Run

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Returns the base 10 logarithm of the number.

let ten = 10.0_f64;

// log10(10) - 1 == 0
let abs_difference = (ten.log10() - 1.0).abs();

assert!(abs_difference < 1e-10);Run

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Converts radians to degrees.

use std::f64::consts;

let angle = consts::PI;

let abs_difference = (angle.to_degrees() - 180.0).abs();

assert!(abs_difference < 1e-10);Run

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Converts degrees to radians.

use std::f64::consts;

let angle = 180.0_f64;

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

assert!(abs_difference < 1e-10);Run

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Returns the maximum of the two numbers.

let x = 1.0_f64;
let y = 2.0_f64;

assert_eq!(x.max(y), y);Run

If one of the arguments is NaN, then the other argument is returned.

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Returns the minimum of the two numbers.

let x = 1.0_f64;
let y = 2.0_f64;

assert_eq!(x.min(y), x);Run

If one of the arguments is NaN, then the other argument is returned.

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Deprecated since 1.10.0

: you probably meant (self - other).abs(): this operation is (self - other).max(0.0) (also known as fdim in C). If you truly need the positive difference, consider using that expression or the C function fdim, depending on how you wish to handle NaN (please consider filing an issue describing your use-case too).

The positive difference of two numbers.

  • If self <= other: 0:0
  • Else: self - other
let x = 3.0_f64;
let y = -3.0_f64;

let abs_difference_x = (x.abs_sub(1.0) - 2.0).abs();
let abs_difference_y = (y.abs_sub(1.0) - 0.0).abs();

assert!(abs_difference_x < 1e-10);
assert!(abs_difference_y < 1e-10);Run

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Takes the cubic root of a number.

let x = 8.0_f64;

// x^(1/3) - 2 == 0
let abs_difference = (x.cbrt() - 2.0).abs();

assert!(abs_difference < 1e-10);Run

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Calculates the length of the hypotenuse of a right-angle triangle given legs of length x and y.

let x = 2.0_f64;
let y = 3.0_f64;

// sqrt(x^2 + y^2)
let abs_difference = (x.hypot(y) - (x.powi(2) + y.powi(2)).sqrt()).abs();

assert!(abs_difference < 1e-10);Run

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Computes the sine of a number (in radians).

use std::f64;

let x = f64::consts::PI/2.0;

let abs_difference = (x.sin() - 1.0).abs();

assert!(abs_difference < 1e-10);Run

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Computes the cosine of a number (in radians).

use std::f64;

let x = 2.0*f64::consts::PI;

let abs_difference = (x.cos() - 1.0).abs();

assert!(abs_difference < 1e-10);Run

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Computes the tangent of a number (in radians).

use std::f64;

let x = f64::consts::PI/4.0;
let abs_difference = (x.tan() - 1.0).abs();

assert!(abs_difference < 1e-14);Run

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Computes the arcsine of a number. Return value is in radians in the range [-pi/2, pi/2] or NaN if the number is outside the range [-1, 1].

use std::f64;

let f = f64::consts::PI / 2.0;

// asin(sin(pi/2))
let abs_difference = (f.sin().asin() - f64::consts::PI / 2.0).abs();

assert!(abs_difference < 1e-10);Run

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Computes the arccosine of a number. Return value is in radians in the range [0, pi] or NaN if the number is outside the range [-1, 1].

use std::f64;

let f = f64::consts::PI / 4.0;

// acos(cos(pi/4))
let abs_difference = (f.cos().acos() - f64::consts::PI / 4.0).abs();

assert!(abs_difference < 1e-10);Run

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Computes the arctangent of a number. Return value is in radians in the range [-pi/2, pi/2];

let f = 1.0_f64;

// atan(tan(1))
let abs_difference = (f.tan().atan() - 1.0).abs();

assert!(abs_difference < 1e-10);Run

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Computes the four quadrant arctangent of self (y) and other (x).

  • x = 0, y = 0: 0
  • x >= 0: arctan(y/x) -> [-pi/2, pi/2]
  • y >= 0: arctan(y/x) + pi -> (pi/2, pi]
  • y < 0: arctan(y/x) - pi -> (-pi, -pi/2)
use std::f64;

let pi = f64::consts::PI;
// All angles from horizontal right (+x)
// 45 deg counter-clockwise
let x1 = 3.0_f64;
let y1 = -3.0_f64;

// 135 deg clockwise
let x2 = -3.0_f64;
let y2 = 3.0_f64;

let abs_difference_1 = (y1.atan2(x1) - (-pi/4.0)).abs();
let abs_difference_2 = (y2.atan2(x2) - 3.0*pi/4.0).abs();

assert!(abs_difference_1 < 1e-10);
assert!(abs_difference_2 < 1e-10);Run

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Simultaneously computes the sine and cosine of the number, x. Returns (sin(x), cos(x)).

use std::f64;

let x = f64::consts::PI/4.0;
let f = x.sin_cos();

let abs_difference_0 = (f.0 - x.sin()).abs();
let abs_difference_1 = (f.1 - x.cos()).abs();

assert!(abs_difference_0 < 1e-10);
assert!(abs_difference_1 < 1e-10);Run

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Returns e^(self) - 1 in a way that is accurate even if the number is close to zero.

let x = 7.0_f64;

// e^(ln(7)) - 1
let abs_difference = (x.ln().exp_m1() - 6.0).abs();

assert!(abs_difference < 1e-10);Run

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Returns ln(1+n) (natural logarithm) more accurately than if the operations were performed separately.

use std::f64;

let x = f64::consts::E - 1.0;

// ln(1 + (e - 1)) == ln(e) == 1
let abs_difference = (x.ln_1p() - 1.0).abs();

assert!(abs_difference < 1e-10);Run

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Hyperbolic sine function.

use std::f64;

let e = f64::consts::E;
let x = 1.0_f64;

let f = x.sinh();
// Solving sinh() at 1 gives `(e^2-1)/(2e)`
let g = (e*e - 1.0)/(2.0*e);
let abs_difference = (f - g).abs();

assert!(abs_difference < 1e-10);Run

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Hyperbolic cosine function.

use std::f64;

let e = f64::consts::E;
let x = 1.0_f64;
let f = x.cosh();
// Solving cosh() at 1 gives this result
let g = (e*e + 1.0)/(2.0*e);
let abs_difference = (f - g).abs();

// Same result
assert!(abs_difference < 1.0e-10);Run

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Hyperbolic tangent function.

use std::f64;

let e = f64::consts::E;
let x = 1.0_f64;

let f = x.tanh();
// Solving tanh() at 1 gives `(1 - e^(-2))/(1 + e^(-2))`
let g = (1.0 - e.powi(-2))/(1.0 + e.powi(-2));
let abs_difference = (f - g).abs();

assert!(abs_difference < 1.0e-10);Run

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Inverse hyperbolic sine function.

let x = 1.0_f64;
let f = x.sinh().asinh();

let abs_difference = (f - x).abs();

assert!(abs_difference < 1.0e-10);Run

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Inverse hyperbolic cosine function.

let x = 1.0_f64;
let f = x.cosh().acosh();

let abs_difference = (f - x).abs();

assert!(abs_difference < 1.0e-10);Run

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Inverse hyperbolic tangent function.

use std::f64;

let e = f64::consts::E;
let f = e.tanh().atanh();

let abs_difference = (f - e).abs();

assert!(abs_difference < 1.0e-10);Run

1.20.0
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Raw transmutation to u64.

Converts the f64 into its raw memory representation, similar to the transmute function.

Note that this function is distinct from casting.

Examples

assert!((1f64).to_bits() != 1f64 as u64); // to_bits() is not casting!
assert_eq!((12.5f64).to_bits(), 0x4029000000000000);
Run

1.20.0
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Raw transmutation from u64.

Converts the given u64 containing the float's raw memory representation into the f64 type, similar to the transmute function.

There is only one difference to a bare transmute: Due to the implications onto Rust's safety promises being uncertain, if the representation of a signaling NaN "sNaN" float is passed to the function, the implementation is allowed to return a quiet NaN instead.

Note that this function is distinct from casting.

Examples

use std::f64;
let v = f64::from_bits(0x4029000000000000);
let difference = (v - 12.5).abs();
assert!(difference <= 1e-5);
// Example for a signaling NaN value:
let snan = 0x7FF0000000000001;
assert_ne!(f64::from_bits(snan).to_bits(), snan);Run

Trait Implementations

impl<'a, 'b> Add<&'a f64> for &'b f64
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The resulting type after applying the + operator.

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Performs the + operation.

impl<'a> Add<&'a f64> for f64
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The resulting type after applying the + operator.

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Performs the + operation.

impl Add<f64> for f64
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The resulting type after applying the + operator.

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Performs the + operation.

impl<'a> Add<f64> for &'a f64
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The resulting type after applying the + operator.

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Performs the + operation.

impl PartialEq<f64> for f64
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This method tests for self and other values to be equal, and is used by ==. Read more

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This method tests for !=.

impl UpperExp for f64
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Formats the value using the given formatter.

impl DivAssign<f64> for f64
1.8.0
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Performs the /= operation.

impl<'a> DivAssign<&'a f64> for f64
1.22.0
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Performs the /= operation.

impl<'a> SubAssign<&'a f64> for f64
1.22.0
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Performs the -= operation.

impl SubAssign<f64> for f64
1.8.0
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Performs the -= operation.

impl<'a> Product<&'a f64> for f64
1.12.0
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Method which takes an iterator and generates Self from the elements by multiplying the items. Read more

impl Product<f64> for f64
1.12.0
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Method which takes an iterator and generates Self from the elements by multiplying the items. Read more

impl<'a> Mul<f64> for &'a f64
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The resulting type after applying the * operator.

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Performs the * operation.

impl<'a> Mul<&'a f64> for f64
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The resulting type after applying the * operator.

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Performs the * operation.

impl<'a, 'b> Mul<&'a f64> for &'b f64
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The resulting type after applying the * operator.

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Performs the * operation.

impl Mul<f64> for f64
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The resulting type after applying the * operator.

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Performs the * operation.

impl FromStr for f64
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The associated error which can be returned from parsing.

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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', 'NaN'

Leading and trailing whitespace represent an error.

Arguments

  • src - A string

Return value

Err(ParseFloatError) if the string did not represent a valid number. Otherwise, Ok(n) where n is the floating-point number represented by src.

impl Debug for f64
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Formats the value using the given formatter.

impl Default for f64
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Returns the default value of 0.0

impl PartialOrd<f64> for f64
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This method returns an ordering between self and other values if one exists. Read more

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This method tests less than (for self and other) and is used by the < operator. Read more

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This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

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This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

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This method tests greater than (for self and other) and is used by the > operator. Read more

impl From<u16> for f64
1.6.0
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Performs the conversion.

impl From<i32> for f64
1.6.0
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Performs the conversion.

impl From<i8> for f64
1.6.0
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Performs the conversion.

impl From<u32> for f64
1.6.0
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Performs the conversion.

impl From<u8> for f64
1.6.0
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Performs the conversion.

impl From<i16> for f64
1.6.0
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Performs the conversion.

impl From<f32> for f64
1.6.0
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Performs the conversion.

impl<'a> RemAssign<&'a f64> for f64
1.22.0
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Performs the %= operation.

impl RemAssign<f64> for f64
1.8.0
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Performs the %= operation.

impl MulAssign<f64> for f64
1.8.0
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Performs the *= operation.

impl<'a> MulAssign<&'a f64> for f64
1.22.0
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Performs the *= operation.

impl AddAssign<f64> for f64
1.8.0
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Performs the += operation.

impl<'a> AddAssign<&'a f64> for f64
1.22.0
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Performs the += operation.

impl<'a> Neg for &'a f64
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The resulting type after applying the - operator.

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Performs the unary - operation.

impl Neg for f64
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The resulting type after applying the - operator.

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Performs the unary - operation.

impl Sub<f64> for f64
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The resulting type after applying the - operator.

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Performs the - operation.

impl<'a> Sub<&'a f64> for f64
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The resulting type after applying the - operator.

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Performs the - operation.

impl<'a> Sub<f64> for &'a f64
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The resulting type after applying the - operator.

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Performs the - operation.

impl<'a, 'b> Sub<&'a f64> for &'b f64
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The resulting type after applying the - operator.

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Performs the - operation.

impl LowerExp for f64
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Formats the value using the given formatter.

impl Display for f64
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Formats the value using the given formatter. Read more

impl<'a> Rem<&'a f64> for f64
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The resulting type after applying the % operator.

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Performs the % operation.

impl<'a> Rem<f64> for &'a f64
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The resulting type after applying the % operator.

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Performs the % operation.

impl<'a, 'b> Rem<&'a f64> for &'b f64
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The resulting type after applying the % operator.

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Performs the % operation.

impl Rem<f64> for f64
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The resulting type after applying the % operator.

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Performs the % operation.

impl Sum<f64> for f64
1.12.0
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Method which takes an iterator and generates Self from the elements by "summing up" the items. Read more

impl<'a> Sum<&'a f64> for f64
1.12.0
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Method which takes an iterator and generates Self from the elements by "summing up" the items. Read more

impl<'a> Div<&'a f64> for f64
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The resulting type after applying the / operator.

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Performs the / operation.

impl Div<f64> for f64
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The resulting type after applying the / operator.

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Performs the / operation.

impl<'a> Div<f64> for &'a f64
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The resulting type after applying the / operator.

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Performs the / operation.

impl<'a, 'b> Div<&'a f64> for &'b f64
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The resulting type after applying the / operator.

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Performs the / operation.