diff options
| -rwxr-xr-x | Lib/rational.py | 32 |
1 files changed, 16 insertions, 16 deletions
diff --git a/Lib/rational.py b/Lib/rational.py index dcdaad4..b45da13 100755 --- a/Lib/rational.py +++ b/Lib/rational.py @@ -106,48 +106,48 @@ class Rational(RationalAbc): self._denominator = int(denominator // g) return self - @classmethod - def from_float(cls, f): + @staticmethod + def from_float(f): """Converts a finite float to a rational number, exactly. Beware that Rational.from_float(0.3) != Rational(3, 10). """ if not isinstance(f, float): - raise TypeError("%s.from_float() only takes floats, not %r (%s)" % - (cls.__name__, f, type(f).__name__)) + raise TypeError("Rational.from_float() only takes floats, " + "not %r (%s)" % (f, type(f).__name__)) if math.isnan(f) or math.isinf(f): - raise TypeError("Cannot convert %r to %s." % (f, cls.__name__)) - return cls(*f.as_integer_ratio()) + raise TypeError("Cannot convert %r to Rational." % f) + return Rational(*f.as_integer_ratio()) - @classmethod - def from_decimal(cls, dec): + @staticmethod + def from_decimal(dec): """Converts a finite Decimal instance to a rational number, exactly.""" from decimal import Decimal if not isinstance(dec, Decimal): raise TypeError( - "%s.from_decimal() only takes Decimals, not %r (%s)" % - (cls.__name__, dec, type(dec).__name__)) + "Rational.from_decimal() only takes Decimals, not %r (%s)" % + (dec, type(dec).__name__)) if not dec.is_finite(): # Catches infinities and nans. - raise TypeError("Cannot convert %s to %s." % (dec, cls.__name__)) + raise TypeError("Cannot convert %s to Rational." % dec) sign, digits, exp = dec.as_tuple() digits = int(''.join(map(str, digits))) if sign: digits = -digits if exp >= 0: - return cls(digits * 10 ** exp) + return Rational(digits * 10 ** exp) else: - return cls(digits, 10 ** -exp) + return Rational(digits, 10 ** -exp) - @classmethod - def from_continued_fraction(cls, seq): + @staticmethod + def from_continued_fraction(seq): 'Build a Rational from a continued fraction expessed as a sequence' n, d = 1, 0 for e in reversed(seq): n, d = d, n n += e * d - return cls(n, d) if seq else cls(0) + return Rational(n, d) if seq else Rational(0) def as_continued_fraction(self): 'Return continued fraction expressed as a list' |