The program manipulates the data no differently than with other Python numeric With context set and decimals created, the bulk of And, in many applications, data is converted to Decimal withĪ single cast inside a loop. Most programs adjust the current context only once, at the beginning of the traps = 1 > Decimal ( 1 ) / Decimal ( 0 ) Traceback (most recent call last):įile "", line 1, in -toplevel- Decimal ( 1 ) / Decimal ( 0 ) DivisionByZero: x / 0 > setcontext ( ExtendedContext ) > Decimal ( 1 ) / Decimal ( 0 ) Decimal('Infinity') > getcontext (). Reset them before monitoring a calculation. When a signal isĮncountered, its flag is set to one, then, if the trap enabler is The signals in theĭecimal module are: Clamped, InvalidOperation,ĭivisionByZero, Inexact, Rounded, Subnormal,įor each signal there is a flag and a trap enabler. Depending on the needs of the application, signals may be ignored,Ĭonsidered as informational, or treated as exceptions. Signals are groups of exceptional conditions arising during the course ofĬomputation. ROUND_FLOOR, ROUND_HALF_DOWN, ROUND_HALF_EVEN, Options include ROUND_CEILING, ROUND_DOWN, Rules, limits on exponents, flags indicating the results of operations, and trapĮnablers which determine whether signals are treated as exceptions. The context for arithmetic is an environment specifying precision, rounding
Decimals also include special values such as To preserve significance, the coefficient digits do not truncate It has a sign, coefficient digits, and anĮxponent. The module design is centered around three concepts: the decimal number, theĪ decimal number is immutable. Unrounded decimal arithmetic (sometimes called fixed-point arithmetic)Īnd rounded floating-point arithmetic.” – excerpt from the decimal The decimal module was designed to support “without prejudice, both exact
This includes an option to enforce exact arithmetic by using exceptions
#Convert float to string python full
When needed, the programmer has full control over rounding and signal handling. While the built-in float type exposes only a modest portion of itsĬapabilities, the decimal module exposes all required parts of the standard. prec = 28 > Decimal ( 1 ) / Decimal ( 7 ) Decimal('0.1428571428571428571428571429')īoth binary and decimal floating point are implemented in terms of published Unlike hardware based binary floating point, the decimal module has a userĪlterable precision (defaulting to 28 places) which can be as large as needed for Multiplication, the “schoolbook” approach uses all the figures in the This is the customary presentation for monetary applications. The trailing zero is kept to indicate significance. The decimal module incorporates a notion of significant places so that 1.30 + 1.20 is 2.50. Reason, decimal is preferred in accounting applications which have strict Prevent reliable equality testing and differences can accumulate. In decimal floating point, 0.1 + 0.1 + 0.1 - 0.3 is exactly equal to zero. The exactness carries over into arithmetic. End users typically would not expect 1.1 + 2.2 to displayĪs 3.3000000000000003 as it does with binary floating point. In contrast, numbers likeġ.1 and 2.2 do not have exact representations in binaryįloating point. People learn at school.” – excerpt from the decimal arithmetic specification.ĭecimal numbers can be represented exactly. Provide an arithmetic that works in the same way as the arithmetic that In mind, and necessarily has a paramount guiding principle – computers must It offers several advantages over theĭecimal “is based on a floating-point model which was designed with people The decimal module provides support for fast correctly roundedĭecimal floating point arithmetic. Decimal - Decimal fixed point and floating point arithmetic ¶
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