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...float_times(), can be added to set globally the timestamp type. A global flag may cause issues with libraries and applications expecting float instead of Decimal. Decimal is not fully compatible with float. float+Decimal raises a TypeError for example. The os.stat_float_times() case is different because an int can be coerced to float and int+float gives float. Add a protocol to create a timestamp Instead of hard coding how timestamps are created, a new protocol can be added to create a timesta...
...floatkind is the kind object of the corresponding float type. Examples In module myprecision.py: import kinds tinyint = kinds.int_kind(1) single = kinds.float_kind(6, 90) double = kinds.float_kind(15, 300) csingle = kinds.complex_kind(6, 90) In the rest of my code: from myprecision import tinyint, single, double, csingle n = tinyint(3) x = double(1.e20) z = 1.2 # builtin float gets you the default float kind, properties unknown w = x * float(x) # but in the following case we know w has kind...
...float and then apply a float division. That is, even 2/1 will return a float (2.0), not an int. For floats and complex, it will be the same as classic division. The 2.2 implementation of true division acts as if the float type had unbounded range, so that overflow doesn't occur unless the magnitude of the mathematical result is too large to represent as a float. For example, after x = 1L << 40000, float(x) raises OverflowError (note that this is also new in 2.2: previously the outcome w...
...float('inf') and repr(float('inf')) are now guaranteed to work on every supported platform with IEEE 754 semantics. However the eval(repr(float('inf'))) roundtrip is still not supported unless you define inf and nan yourself: >>> inf = float('inf') >>> inf, 1E400 (inf, inf) >>> neginf = float('-inf') >>> neginf, -1E400 (-inf, -inf) >>> nan = float('nan') >>> nan, inf * 0. (nan, nan) The math and the sys module also have gained additional fe...
...float = 1.0 def set_scale(self, scale: float) -> Self: self.scale = scale return self class ReturnConcreteShape: scale: float = 1.0 def set_scale(self, scale: float) -> ReturnConcreteShape: self.scale = scale return self class BadReturnType: scale: float = 1.0 def set_scale(self, scale: float) -> int: self.scale = scale return 42 class ReturnDifferentClass: scale: float = 1.0 def set_scale(self, scale: fl...
...float__(self): """float(self) == float(int(self))""" return float(int(self)) @property def numerator(self): """Integers are their own numerators.""" return +self @property def denominator(self): """Integers have a denominator of 1.""" return 1 Changes to operations and __magic__ methods To support more precise narrowing from float to int (and more generally, from Real to Integral), we propose the following new __magic__ methods...
...float. Instead you must use a method: Decimal.from_float(). The syntax: Decimal.from_float(floatNumber, [decimal_places]) where floatNumber is the float number origin of the construction and decimal_places are the number of digits after the decimal point where you apply a round-half-up rounding, if any. In this way you can do, for example: Decimal.from_float(1.1, 2): The same as doing Decimal('1.1'). Decimal.from_float(1.1, 16): The same as doing Decimal('1.1000000000000001'). Decimal.from_f...
...float types The primary use-case is expected to be floating point numbers. However, users may want to compare other numeric types similarly. In theory, it should work for any type that supports abs(), multiplication, comparisons, and subtraction. However, the implementation in the math module is written in C, and thus can not (easily) use python's duck typing. Rather, the values passed into the function will be converted to the float type before the calculation is performed. Passing in types (or...
...floating point literals, they should be suffixed with "e0". Python 3.1 will have the warning turned off by default. This warning will stay in place for 24 months, at which time the literals will be rationals and the warning will be removed. Common Objections Rationals are slow and memory intensive! (Relax, I'm not taking floats away, I'm just adding two more characters. 1e0 will still be a float) Rationals must present themselves as a decimal float or they will be horrible for users expectin...
...float) -> float: return 2*x def contra(x: float) -> float: return -x def inv(x: float) -> float: return x*x If x1 < x2, then always cov(x1) < cov(x2), and contra(x2) < contra(x1), while nothing could be said about inv. Replacing < with is-subtype-of, and functions with generic type constructor we get examples of covariant, contravariant, and invariant behavior. Let us now consider practical examples: Union behaves covariantly in all its arguments. Indeed, as ...
...floatobject.c:PyFloat_FromString() Objects/floatobject.c:format_float() Objects/stringobject.c:formatfloat() Modules/stropmodule.c:strop_atof() Modules/cPickle.c:load_float() The proposed approach is to implement LC_NUMERIC-agnostic functions for converting from (strtod()/atof()) and to (snprintf()) float formats, using these functions where the formatting should not vary according to the user-specified locale. The locale module should also be changed to remove the special-casing for LC_NUMERIC...
...floats may be broken when the comparison involves conversion to float. Ditto for comparisons between longs and floats. This can be dealt with by avoiding the conversion to float. (Due to Andrew Koenig.) Copyright This document has been placed in the public domain. Source: https://github.com/python/peps/blob/master/pep-0228.txt
...float, str] def f(list: List[int | str], param: int | None) -> float | str: pass f([1, "abc"], None) # Instead of typing.List[typing.Union[str, int]] typing.List[str | int] list[str | int] # Instead of typing.Dict[str, typing.Union[int, float]] typing.Dict[str, int | float] dict[str, int | float] The existing typing.Union and | syntax should be equivalent. int | str == typing.Union[int, str] typing.Union[int, int] == int int | int == int The order of the items in the Union should n...
...floating-point number which is usually a 64-bit binary floating-point number (in the IEEE 754 format). The problem is that the float type starts to lose nanoseconds after 104 days. Converting from nanoseconds (int) to seconds (float) and then back to nanoseconds (int) to check if conversions lose precision: # no precision loss >>> x = 2 ** 52 + 1; int(float(x * 1e-9) * 1e9) - x 0 # precision loss! (1 nanosecond) >>> x = 2 ** 53 + 1; int(float(x * 1e-9) * 1e9) - x -1 >>&...
...float, and complex. Therefore, an operation between a Python integer and an Int16 (short) array will return an Int16 array. Whereas an operation between a Python float and an Int16 array would return a Float64 (double) array. Operations between two arrays use normal coercion rules. How is integer division handled? In a future version of Python, the behavior of integer division will change. The operands will be converted to floats, so the result will be a float. If we implement the proposed...
...floating point bounds for an integer loop: if a float represents an inexact value, how can it be used to determine an exact sequence of integers? On the other hand, disallowing float bounds would make it difficult to use floor() and ceiling() in integer for-loops, as it is difficult to use them now with range(). We have erred on the side of flexibility, but this may lead to some implementation difficulties in determining the smallest and largest integer values that would cause a given comparis...
...float) bar(low,high): pass def foo @classmethod (arg1,arg2): pass def bar @accepts(int,int),@returns(float) (low,high): pass There are a couple of objections to this form. The first is that it breaks easily 'greppability' of the source -- you can no longer search for 'def foo(' and find the definition of the function. The second, more serious, objection is that in the case of multiple decorators, the syntax would be extremely unwieldy. The next form, which has had a number of st...
...floating-point and complex literals: floatnumber: pointfloat | exponentfloat pointfloat: [digitpart] fraction | digitpart "." exponentfloat: (digitpart | pointfloat) exponent digitpart: digit (["_"] digit)* fraction: "." digitpart exponent: ("e" | "E") ["+" | "-"] digitpart imagnumber: (floatnumber | digitpart) ("j" | "J") Constructors Following the same rules for placement, underscores will be allowed in the following constructors: int() (with any base) float() complex() Decimal() Furth...
...float now raises OverflowError if the long is too big to represent as a C double. This used to return an "infinity" value on most platforms. <p><li> The 3-argument builtin pow() no longer allows a third non-None argument if either of the first two arguments is a float, or if both are of integer types and the second argument is negative (in which latter case the arguments are converted to float, so this is really the same restriction). <p><li>An old tokenizer bu...