Module decimal :: Class Decimal

Class Decimal

object --+
         |
        Decimal

Floating point class for decimal arithmetic.

Instance Methods

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_isnan(self)
Returns whether the number is not actually one.

_isinfinity(self)
Returns whether the number is infinite

_check_nans(self, other=None, context=None)
Returns whether the number is not actually one.

__nonzero__(self)
Is the number non-zero?

__cmp__(self, other, context=None)

__eq__(self, other)

__ne__(self, other)

compare(self, other, context=None)
Compares one to another.

__hash__(x)
hash(x)

as_tuple(self)
Represents the number as a triple tuple.

__repr__(self)
Represents the number as an instance of Decimal.

__str__(self, eng=0, context=None)
Return string representation of the number in scientific notation.

to_eng_string(self, context=None)
Convert to engineering-type string.

__neg__(self, context=None)
Returns a copy with the sign switched.

__pos__(self, context=None)
Returns a copy, unless it is a sNaN.

__abs__(self, round=1, context=None)
Returns the absolute value of self.

__add__(self, other, context=None)
Returns self + other.

__radd__(self, other, context=None)
Returns self + other.

__sub__(self, other, context=None)
Return self + (-other)

__rsub__(self, other, context=None)
Return other + (-self)

_increment(self, round=1, context=None)
Special case of add, adding 1eExponent

__mul__(self, other, context=None)
Return self * other.

__rmul__(self, other, context=None)
Return self * other.

__div__(self, other, context=None)
Return self / other.

__truediv__(self, other, context=None)
Return self / other.

_divide(self, other, divmod=0, context=None)
Return a / b, to context.prec precision.

__rdiv__(self, other, context=None)
Swaps self/other and returns __div__.

__rtruediv__(self, other, context=None)
Swaps self/other and returns __div__.

__divmod__(self, other, context=None)
(self // other, self % other)

__rdivmod__(self, other, context=None)
Swaps self/other and returns __divmod__.

__mod__(self, other, context=None)
self % other

__rmod__(self, other, context=None)
Swaps self/other and returns __mod__.

remainder_near(self, other, context=None)
Remainder nearest to 0- abs(remainder-near) <= other/2

__floordiv__(self, other, context=None)
self // other

__rfloordiv__(self, other, context=None)
Swaps self/other and returns __floordiv__.

__float__(self)
Float representation.

__int__(self)
Converts self to an int, truncating if necessary.

__long__(self)
Converts to a long.

_fix(self, context)
Round if it is necessary to keep self within prec precision.

_fixexponents(self, context)
Fix the exponents and return a copy with the exponent in bounds.

_round(self, prec=None, rounding=None, context=None)
Returns a rounded version of self.

_round_down(self, prec, expdiff, context)
Also known as round-towards-0, truncate.

_round_half_up(self, prec, expdiff, context, tmp=None)
Rounds 5 up (away from 0)

_round_half_even(self, prec, expdiff, context)
Round 5 to even, rest to nearest.

_round_half_down(self, prec, expdiff, context)
Round 5 down

_round_up(self, prec, expdiff, context)
Rounds away from 0.

_round_ceiling(self, prec, expdiff, context)
Rounds up (not away from 0 if negative.)

_round_floor(self, prec, expdiff, context)
Rounds down (not towards 0 if negative)

__pow__(self, n, modulo=None, context=None)
Return self ** n (mod modulo)

__rpow__(self, other, context=None)
Swaps self/other and returns __pow__.

normalize(self, context=None)
Normalize- strip trailing 0s, change anything equal to 0 to 0e0

quantize(self, exp, rounding=None, context=None, watchexp=1)
Quantize self so its exponent is the same as that of exp.

same_quantum(self, other)
Test whether self and other have the same exponent.

_rescale(self, exp, rounding=None, context=None, watchexp=1)
Rescales so that the exponent is exp.

to_integral(self, rounding=None, context=None)
Rounds to the nearest integer, without raising inexact, rounded.

sqrt(self, context=None)
Return the square root of self.

max(self, other, context=None)
Returns the larger value.

min(self, other, context=None)
Returns the smaller value.

_isinteger(self)
Returns whether self is an integer

_iseven(self)
Returns 1 if self is even.

adjusted(self)
Return the adjusted exponent of self

__reduce__(self)
helper for pickle

__copy__(self)

__deepcopy__(self, memo)

Inherited from object: __delattr__, __getattribute__, __init__, __reduce_ex__, __setattr__

Static Methods

[hide private]

a new object with type S, a subtype of T

__new__(cls, value='0', context=None)
Create a decimal point instance.

Class Variables

[hide private]

_pick_rounding_function = {'ROUND_CEILING': '_round_ceiling', ...

Properties

[hide private]

_exp

_int

_is_special

_sign

Inherited from object: __class__

Method Details

[hide private]

new(cls, value=`'0'`, context=None)
Static Method

Create a decimal point instance.

>>> Decimal('3.14')              # string input
Decimal("3.14")
>>> Decimal((0, (3, 1, 4), -2))  # tuple input (sign, digit_tuple, exponent)
Decimal("3.14")
>>> Decimal(314)                 # int or long
Decimal("314")
>>> Decimal(Decimal(314))        # another decimal instance
Decimal("314")

Returns: a new object with type S, a subtype of T
Overrides: object.__new__

_isnan(self)

Returns whether the number is not actually one.

0 if a number 1 if NaN 2 if sNaN

_isinfinity(self)

Returns whether the number is infinite

0 if finite or not a number 1 if +INF -1 if -INF

_check_nans(self, other=None, context=None)

Returns whether the number is not actually one.

if self, other are sNaN, signal if self, other are NaN return nan return 0

Done before operations.

nonzero(self)
(Boolean test operator)

Is the number non-zero?

0 if self == 0 1 if self != 0

compare(self, other, context=None)

Compares one to another.

-1 => a < b 0 => a = b 1 => a > b NaN => one is NaN Like __cmp__, but returns Decimal instances.

hash(x)
(Hashing function)

hash(x)

Overrides: object.__hash__

as_tuple(self)

Represents the number as a triple tuple.

To show the internals exactly as they are.

repr(self)
(Representation operator)

Represents the number as an instance of Decimal.

Overrides: object.__repr__

str(self, eng=0, context=None)
(Informal representation operator)

Return string representation of the number in scientific notation.

Captures all of the information in the underlying representation.

Overrides: object.__str__

to_eng_string(self, context=None)

Convert to engineering-type string.

Engineering notation has an exponent which is a multiple of 3, so there are up to 3 digits left of the decimal place.

Same rules for when in exponential and when as a value as in __str__.

neg(self, context=None)

Returns a copy with the sign switched.

Rounds, if it has reason.

pos(self, context=None)

Returns a copy, unless it is a sNaN.

Rounds the number (if more then precision digits)

abs(self, round=1, context=None)

Returns the absolute value of self.

If the second argument is 0, do not round.

add(self, other, context=None)
(Addition operator)

Returns self + other.

-INF + INF (or the reverse) cause InvalidOperation errors.

radd(self, other, context=None)
(Right-side addition operator)

Returns self + other.

-INF + INF (or the reverse) cause InvalidOperation errors.

_increment(self, round=1, context=None)

Special case of add, adding 1eExponent

Since it is common, (rounding, for example) this adds (sign)*one E self._exp to the number more efficiently than add.

For example: Decimal('5.624e10')._increment() == Decimal('5.625e10')

mul(self, other, context=None)

Return self * other.

(+-) INF * 0 (or its reverse) raise InvalidOperation.

rmul(self, other, context=None)

Return self * other.

(+-) INF * 0 (or its reverse) raise InvalidOperation.

_divide(self, other, divmod=0, context=None)

Return a / b, to context.prec precision.

divmod: 0 => true division 1 => (a //b, a%b) 2 => a //b 3 => a%b

Actually, if divmod is 2 or 3 a tuple is returned, but errors for computing the other value are not raised.

long(self)

Converts to a long.

Equivalent to long(int(self))

_fix(self, context)

Round if it is necessary to keep self within prec precision.

Rounds and fixes the exponent. Does not raise on a sNaN.

Arguments: self - Decimal instance context - context used.

_fixexponents(self, context)

Fix the exponents and return a copy with the exponent in bounds. Only call if known to not be a special value.

_round(self, prec=None, rounding=None, context=None)

Returns a rounded version of self.

You can specify the precision or rounding method. Otherwise, the context determines it.

pow(self, n, modulo=None, context=None)

Return self ** n (mod modulo)

If modulo is None (default), don't take it mod modulo.

quantize(self, exp, rounding=None, context=None, watchexp=1)

Quantize self so its exponent is the same as that of exp.

Similar to self._rescale(exp._exp) but with error checking.

same_quantum(self, other)

Test whether self and other have the same exponent.

same as self._exp == other._exp, except NaN == sNaN

_rescale(self, exp, rounding=None, context=None, watchexp=1)

Rescales so that the exponent is exp.

exp = exp to scale to (an integer) rounding = rounding version watchexp: if set (default) an error is returned if exp is greater than Emax or less than Etiny.

sqrt(self, context=None)

Return the square root of self.

Uses a converging algorithm (Xn+1 = 0.5*(Xn + self / Xn)) Should quadratically approach the right answer.

max(self, other, context=None)

Returns the larger value.

like max(self, other) except if one is not a number, returns NaN (and signals if one is sNaN). Also rounds.

min(self, other, context=None)

Returns the smaller value.

like min(self, other) except if one is not a number, returns NaN (and signals if one is sNaN). Also rounds.

_iseven(self)

Returns 1 if self is even. Assumes self is an integer.

reduce(self)

helper for pickle

Overrides: object.__reduce__: (inherited documentation)

Class Variable Details

[hide private]

_pick_rounding_function

Value:

{'ROUND_CEILING': '_round_ceiling',
 'ROUND_DOWN': '_round_down',
 'ROUND_FLOOR': '_round_floor',
 'ROUND_HALF_DOWN': '_round_half_down',
 'ROUND_HALF_EVEN': '_round_half_even',
 'ROUND_HALF_UP': '_round_half_up',
 'ROUND_UP': '_round_up'}

Class Decimal

__new__(cls, value='0', context=None) Static Method

_isnan(self)

_isinfinity(self)

_check_nans(self, other=None, context=None)

__nonzero__(self) (Boolean test operator)

compare(self, other, context=None)

__hash__(x) (Hashing function)

as_tuple(self)

__repr__(self) (Representation operator)

__str__(self, eng=0, context=None) (Informal representation operator)

to_eng_string(self, context=None)

__neg__(self, context=None)

__pos__(self, context=None)

__abs__(self, round=1, context=None)

__add__(self, other, context=None) (Addition operator)

__radd__(self, other, context=None) (Right-side addition operator)

_increment(self, round=1, context=None)

__mul__(self, other, context=None)

__rmul__(self, other, context=None)

_divide(self, other, divmod=0, context=None)

__long__(self)

_fix(self, context)

_fixexponents(self, context)

_round(self, prec=None, rounding=None, context=None)

__pow__(self, n, modulo=None, context=None)

quantize(self, exp, rounding=None, context=None, watchexp=1)

same_quantum(self, other)

_rescale(self, exp, rounding=None, context=None, watchexp=1)

sqrt(self, context=None)

max(self, other, context=None)

min(self, other, context=None)

_iseven(self)

__reduce__(self)

_pick_rounding_function

new(cls, value=`'0'`, context=None)
Static Method

nonzero(self)
(Boolean test operator)

hash(x)
(Hashing function)

repr(self)
(Representation operator)

str(self, eng=0, context=None)
(Informal representation operator)

neg(self, context=None)

pos(self, context=None)

abs(self, round=1, context=None)

add(self, other, context=None)
(Addition operator)

radd(self, other, context=None)
(Right-side addition operator)

mul(self, other, context=None)

rmul(self, other, context=None)

long(self)

pow(self, n, modulo=None, context=None)

reduce(self)