tessl/golang-github-com-shopspring--decimal
Arbitrary-precision fixed-point decimal numbers for Go, avoiding floating-point precision issues with support for arithmetic, rounding, serialization, and database integration.
rounding.mddocs/api/
Rounding
Multiple rounding strategies for financial and general-purpose use. All methods return new Decimal values.
Negative places values round the integer part (e.g., places=-1 rounds to nearest 10).
Capabilities
Round (Half-Up)
Rounds to places decimal places. If the digit to be rounded is exactly 5, rounds away from zero (half-up).
// Round rounds to places decimal places using half-up rounding.
// If places < 0, rounds the integer part to the nearest 10^(-places).
func (d Decimal) Round(places int32) DecimalUsage:
decimal.NewFromFloat(5.45).Round(1).String() // "5.5"
decimal.NewFromFloat(5.44).Round(1).String() // "5.4"
decimal.NewFromFloat(5.445).Round(2).String() // "5.45"
decimal.NewFromFloat(545).Round(-1).String() // "550"
decimal.NewFromFloat(544).Round(-1).String() // "540"RoundBank (Banker's / Half-to-Even)
Rounds to places decimal places using banker's rounding (round half to even). When the digit to round is exactly 5, rounds to the nearest even number.
// RoundBank rounds to places decimal places using banker's rounding (half-to-even).
// If places < 0, rounds the integer part to the nearest 10^(-places).
func (d Decimal) RoundBank(places int32) DecimalUsage:
decimal.NewFromFloat(5.45).RoundBank(1).String() // "5.4" (rounds to even: 4)
decimal.NewFromFloat(5.55).RoundBank(1).String() // "5.6" (rounds to even: 6)
decimal.NewFromFloat(5.46).RoundBank(1).String() // "5.5"
decimal.NewFromFloat(545).RoundBank(-1).String() // "540" (rounds to even: 4)
decimal.NewFromFloat(555).RoundBank(-1).String() // "560" (rounds to even: 6)RoundUp (Away from Zero)
Rounds away from zero in all cases (ceiling for positive, floor for negative).
// RoundUp rounds the decimal away from zero.
// If places < 0, rounds the integer part to the nearest 10^(-places).
func (d Decimal) RoundUp(places int32) DecimalUsage:
decimal.NewFromFloat(545).RoundUp(-2).String() // "600"
decimal.NewFromFloat(500).RoundUp(-2).String() // "500"
decimal.NewFromFloat(1.1001).RoundUp(2).String() // "1.11"
decimal.NewFromFloat(-1.454).RoundUp(1).String() // "-1.5"RoundDown (Towards Zero / Truncation)
Rounds towards zero in all cases.
// RoundDown rounds the decimal towards zero.
// If places < 0, rounds the integer part to the nearest 10^(-places).
func (d Decimal) RoundDown(places int32) DecimalUsage:
decimal.NewFromFloat(545).RoundDown(-2).String() // "500"
decimal.NewFromFloat(-500).RoundDown(-2).String() // "-500"
decimal.NewFromFloat(1.1001).RoundDown(2).String() // "1.1"
decimal.NewFromFloat(-1.454).RoundDown(1).String() // "-1.4"RoundCeil (Towards +Infinity)
Rounds towards positive infinity (ceiling function for decimal places).
// RoundCeil rounds the decimal towards +infinity.
// If places < 0, rounds the integer part to the nearest 10^(-places).
func (d Decimal) RoundCeil(places int32) DecimalUsage:
decimal.NewFromFloat(545).RoundCeil(-2).String() // "600"
decimal.NewFromFloat(500).RoundCeil(-2).String() // "500"
decimal.NewFromFloat(1.1001).RoundCeil(2).String() // "1.11"
decimal.NewFromFloat(-1.454).RoundCeil(1).String() // "-1.4"RoundFloor (Towards -Infinity)
Rounds towards negative infinity (floor function for decimal places).
// RoundFloor rounds the decimal towards -infinity.
// If places < 0, rounds the integer part to the nearest 10^(-places).
func (d Decimal) RoundFloor(places int32) DecimalUsage:
decimal.NewFromFloat(545).RoundFloor(-2).String() // "500"
decimal.NewFromFloat(-500).RoundFloor(-2).String() // "-500"
decimal.NewFromFloat(1.1001).RoundFloor(2).String() // "1.1"
decimal.NewFromFloat(-1.454).RoundFloor(1).String() // "-1.5"RoundCash (Cash / Penny Rounding)
Rounds to the nearest multiple of the minimum currency unit. Used for cash transactions.
// RoundCash rounds decimal to a specific currency interval.
// Valid intervals: 5, 10, 25, 50, 100.
// Panics for any other interval value.
//
// Rounding behavior:
// 5: 5 cent rounding 3.43 => 3.45
// 10: 10 cent rounding 3.45 => 3.50 (5 rounds up)
// 25: 25 cent rounding 3.41 => 3.50
// 50: 50 cent rounding 3.75 => 4.00
// 100: 100 cent rounding 3.50 => 4.00
func (d Decimal) RoundCash(interval uint8) DecimalUsage:
decimal.NewFromFloat(3.43).RoundCash(5).String() // "3.45"
decimal.NewFromFloat(3.47).RoundCash(5).String() // "3.45"
decimal.NewFromFloat(3.45).RoundCash(10).String() // "3.50"
decimal.NewFromFloat(3.41).RoundCash(25).String() // "3.50"
decimal.NewFromFloat(3.75).RoundCash(50).String() // "4.00"
decimal.NewFromFloat(3.50).RoundCash(100).String() // "4.00"Truncate
Removes digits beyond precision decimal places without rounding.
// Truncate truncates off digits from the number without rounding.
// precision is the last digit that will NOT be truncated. Must be >= 0.
func (d Decimal) Truncate(precision int32) DecimalUsage:
d, _ := decimal.NewFromString("123.456")
d.Truncate(2).String() // "123.45"
d.Truncate(1).String() // "123.4"
d.Truncate(0).String() // "123"Floor and Ceil
Round to the nearest integer.
// Floor returns the nearest integer value less than or equal to d.
func (d Decimal) Floor() Decimal
// Ceil returns the nearest integer value greater than or equal to d.
func (d Decimal) Ceil() DecimalUsage:
decimal.NewFromFloat(1.9).Floor().String() // "1"
decimal.NewFromFloat(-1.9).Floor().String() // "-2"
decimal.NewFromFloat(1.1).Ceil().String() // "2"
decimal.NewFromFloat(-1.1).Ceil().String() // "-1"String Representation with Rounding
Methods to format decimal as a string with a fixed number of decimal places:
// StringFixed returns a rounded fixed-point string with places digits after the decimal point.
// Uses half-up rounding.
// If places < 0, see StringFixed docs.
func (d Decimal) StringFixed(places int32) string
// StringFixedBank returns a banker's-rounded fixed-point string with places digits
// after the decimal point.
func (d Decimal) StringFixedBank(places int32) string
// StringFixedCash returns a cash-rounded fixed-point string.
// interval must be one of: 5, 10, 25, 50, 100.
func (d Decimal) StringFixedCash(interval uint8) stringUsage:
decimal.NewFromFloat(0).StringFixed(2) // "0.00"
decimal.NewFromFloat(5.45).StringFixed(0) // "5"
decimal.NewFromFloat(5.45).StringFixed(1) // "5.5"
decimal.NewFromFloat(5.45).StringFixed(2) // "5.45"
decimal.NewFromFloat(5.45).StringFixed(3) // "5.450"
decimal.NewFromFloat(545).StringFixed(-1) // "550"
decimal.NewFromFloat(5.45).StringFixedBank(1) // "5.4"
decimal.NewFromFloat(5.55).StringFixedBank(1) // "5.6"
decimal.NewFromFloat(3.43).StringFixedCash(5) // "3.45"Install with Tessl CLI
npx tessl i tessl/golang-github-com-shopspring--decimal