README
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go-rounding
Rounding and truncation methods for big.Rat to close some of the gap in functionality between Rat and Decimal (such as Java's BigDecimal).
Documentation on GoDoc: http://godoc.org/github.com/wadey/go-rounding.
Why go-rounding?
There are a few other Decimal implementations for Go:
So why does go-rounding exist? big.Rat is a superset of the basic needs for a Decimal representation, the only major thing missing is some nice rounding methods. go-rounding is less than 150 lines of code, so it is easy to review and understand its implementation. If you need more features, you should use one of the above packages.
Benchmark
To run:
go test -v -benchmem -bench .
Example output on go1.5 darwin_amd64 commit 55c986f658
BenchmarkFinite 2000000 651 ns/op 182 B/op 3 allocs/op
BenchmarkFinitePrec 2000000 996 ns/op 244 B/op 5 allocs/op
BenchmarkRoundUp 1000000 2470 ns/op 397 B/op 9 allocs/op
BenchmarkRoundHalfEven 1000000 2458 ns/op 393 B/op 9 allocs/op
BenchmarkTrunc 500000 2669 ns/op 265 B/op 6 allocs/op
Documentation
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Overview ¶
Package rounding provides rounding and truncation methods for big.Rat. It uses the same rounding terminology as Java's BigDecimal.
For more information see the README at:
https://github.com/wadey/go-rounding
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Finite ¶
Finite returns true if x has a finite decimal representation. x is finite if the Denom can be represented as (2**x) * (5**y).
Example ¶
x, _ := new(big.Rat).SetString("0.125")
fmt.Println(Finite(x))
fmt.Println(Finite(big.NewRat(2, 3)))
Output: true false
func FinitePrec ¶
FinitePrec returns the precision of the finite decimal representation of x. WARNING: Running this on a value that does not have a finite decimal representation will panic.
Example ¶
x, _ := new(big.Rat).SetString("0.125")
fmt.Println(FinitePrec(x))
Output: 3
func FiniteString ¶
FiniteString returns the equivalent of x.FloatString(FinitePrec(x)). WARNING: Running this on a value that does not have a finite decimal representation will panic.
Example ¶
x, _ := new(big.Rat).SetString("0.125")
fmt.Println(FiniteString(x))
Output: 0.125
func FiniteStringMin ¶
FiniteStringMin returns the equivalent of x.FloatString(max(FinitePrec(x), prec)). WARNING: Running this on a value that does not have a finite decimal representation will panic.
Example ¶
x, _ := new(big.Rat).SetString("5")
fmt.Println(FiniteStringMin(x, 2))
Output: 5.00
Types ¶
type RoundingMode ¶
RoundingMode describes how to round a given number. sign is the sign of the number (needed when n is zero) n is the integer that should be rounded such that the last digit is zero. l is the current last digit of n. r indicates whether the rest of the original number, after last digit, is non-zero NOTE: This method is only called when rounding is necessary, so if l == 0 it means there was more precision that was already truncated (so r is true). For most cases you shouldn't need to implement this yourself, use one of the provided implementations in the rounding package.
var ( // Up rounds away from zero. Up RoundingMode = roundUp // Down rounds towards zero. Down RoundingMode = roundDown // Ceil rounds towards positive infinity. Ceil RoundingMode = roundCeil // Floor rounds towards negative infinity. Floor RoundingMode = roundFloor // HalfUp rounds towards "nearest neighbor" unless both neighbors are equidistant, in which case round up. HalfUp RoundingMode = roundHalfUp // HalfDown rounds towards "nearest neighbor" unless both neighbors are equidistant, in which case round down. HalfDown RoundingMode = roundHalfDown // HalfEven rounds towards the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor. HalfEven RoundingMode = roundHalfEven )
Source Files