Python fractions模块 —— 分数相关函数

概述这是一简单的模块，搞不懂python为什么不把它并入math模块？>>>importfractions>>>fractions.__all__['Fraction','gcd']>>>fractions.gcd(12,18)Warning(fromwarningsmodule):File"<pyshell#2>",line1Deprecat

这是一简单的模块，搞不懂python为什么不把它并入math模块？

>>> import fractions>>> fractions.__all__['Fraction', 'gcd']>>> fractions.gcd(12,18)Warning (from warnings module):  file "<pyshell#2>", line 1DeprecationWarning: fractions.gcd() is deprecated. Use math.gcd() instead.6>>> fractions.gcd(14,6)2>>> import math>>> math.gcd(14,6)2>>> 

一共就俩，其中一个最大公约数函数gcd()还不推荐使用，用math中的gcd替代。

fractions模块中的类Fraction

class Fraction(numbers.Rational) |  Fraction(numerator=0, denominator=None, *, _normalize=True) |   |  This class implements rational numbers. |   |  In the two-argument form of the constructor, Fraction(8, 6) will |  produce a rational number equivalent to 4/3. Both arguments must |  be Rational. The numerator defaults to 0 and the denominator |  defaults to 1 so that Fraction(3) == 3 and Fraction() == 0. |   |  Fractions can also be constructed from: |   |    - numeric strings similar to those accepted by the |      float constructor (for example, '-2.3' or '1e10') |   |    - strings of the form '123/456' |   |    - float and Decimal instances |   |    - other Rational instances (including integers) |   |  Method resolution order: |      Fraction |      numbers.Rational |      numbers.Real |      numbers.Complex |      numbers.Number |      builtins.object |   |  Methods defined here: |   |  __abs__(a) |      abs(a) |   |  __add__(a, b) |      a + b |   |  __bool__(a) |      a != 0 |   |  __ceil__(a) |      math.ceil(a) |   |  __copy__(self) |   |  __deepcopy__(self, memo) |   |  __divmod__(a, b) |      (a // b, a % b) |   |  __eq__(a, b) |      a == b |   |  __floor__(a) |      math.floor(a) |   |  __floordiv__(a, b) |      a // b |   |  __ge__(a, b) |      a >= b |   |  __gt__(a, b) |      a > b |   |  __hash__(self) |      hash(self) |   |  __le__(a, b) |      a <= b |   |  __lt__(a, b) |      a < b |   |  __mod__(a, b) |      a % b |   |  __mul__(a, b) |      a * b |   |  __neg__(a) |      -a |   |  __pos__(a) |      +a: Coerces a subclass instance to Fraction |   |  __pow__(a, b) |      a ** b |       |      If b is not an integer, the result will be a float or complex |      since roots are generally irrational. If b is an integer, the |      result will be rational. |   |  __radd__(b, a) |      a + b |   |  __rdivmod__(b, a) |      (a // b, a % b) |   |  __reduce__(self) |      Helper for pickle. |   |  __repr__(self) |      repr(self) |   |  __rfloordiv__(b, a) |      a // b |   |  __rmod__(b, a) |      a % b |   |  __rmul__(b, a) |      a * b |   |  __round__(self, ndigits=None) |      round(self, ndigits) |       |      Rounds half toward even. |   |  __rpow__(b, a) |      a ** b |   |  __rsub__(b, a) |      a - b |   |  __rtruediv__(b, a) |      a / b |   |  __str__(self) |      str(self) |   |  __sub__(a, b) |      a - b |   |  __truediv__(a, b) |      a / b |   |  __trunc__(a) |      trunc(a) |   |  as_integer_ratio(self) |      Return the integer ratio as a tuple. |       |      Return a tuple of two integers, whose ratio is equal to the |      Fraction and with a positive denominator. |   |  limit_denominator(self, max_denominator=1000000) |      Closest Fraction to self with denominator at most max_denominator. |       |      >>> Fraction('3.141592653589793').limit_denominator(10) |      Fraction(22, 7) |      >>> Fraction('3.141592653589793').limit_denominator(100) |      Fraction(311, 99) |      >>> Fraction(4321, 8765).limit_denominator(10000) |      Fraction(4321, 8765) |   |  ---------------------------------------------------------------------- |  Class methods defined here: |   |  from_decimal(dec) from abc.ABCMeta |      Converts a finite Decimal instance to a rational number, exactly. |   |  from_float(f) from abc.ABCMeta |      Converts a finite float to a rational number, exactly. |       |      Beware that Fraction.from_float(0.3) != Fraction(3, 10). |   |  ---------------------------------------------------------------------- |  Static methods defined here: |   |  __new__(cls, numerator=0, denominator=None, *, _normalize=True) |      Constructs a Rational. |       |      Takes a string like '3/2' or '1.5', another Rational instance, a |      numerator/denominator pair, or a float. |       |      Examples |      -------- |       |      >>> Fraction(10, -8) |      Fraction(-5, 4) |      >>> Fraction(Fraction(1, 7), 5) |      Fraction(1, 35) |      >>> Fraction(Fraction(1, 7), Fraction(2, 3)) |      Fraction(3, 14) |      >>> Fraction('314') |      Fraction(314, 1) |      >>> Fraction('-35/4') |      Fraction(-35, 4) |      >>> Fraction('3.1415') # conversion from numeric string |      Fraction(6283, 2000) |      >>> Fraction('-47e-2') # string may include a decimal exponent |      Fraction(-47, 100) |      >>> Fraction(1.47)  # direct construction from float (exact conversion) |      Fraction(6620291452234629, 4503599627370496) |      >>> Fraction(2.25) |      Fraction(9, 4) |      >>> Fraction(Decimal('1.47')) |      Fraction(147, 100) |   |  ---------------------------------------------------------------------- |  Readonly propertIEs defined here: |   |  denominator |   |  numerator |   |  ---------------------------------------------------------------------- |  Data and other attributes defined here: |   |  __abstractmethods__ = froZenset() |   |  ---------------------------------------------------------------------- |  Methods inherited from numbers.Rational: |   |  __float__(self) |      float(self) = self.numerator / self.denominator |       |      It's important that this conversion use the integer's "true" |      division rather than casting one sIDe to float before divIDing |      so that ratios of huge integers convert without overflowing. |   |  ---------------------------------------------------------------------- |  Methods inherited from numbers.Real: |   |  __complex__(self) |      complex(self) == complex(float(self), 0) |   |  conjugate(self) |      Conjugate is a no-op for Reals. |   |  ---------------------------------------------------------------------- |  Readonly propertIEs inherited from numbers.Real: |   |  imag |      Real numbers have no imaginary component. |   |  real |      Real numbers are their real component.

函数实例在上述帮助中有......混一篇凑凑数 ^_^

总结

以上是内存溢出为你收集整理的Python fractions模块 —— 分数相关函数全部内容，希望文章能够帮你解决Python fractions模块 —— 分数相关函数所遇到的程序开发问题。

如果觉得内存溢出网站内容还不错，欢迎将内存溢出网站推荐给程序员好友。