# decimal

package
v1.7.6 Latest Latest

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Published: Apr 18, 2024 License: Apache-2.0

## Documentation ¶

### Overview ¶

Package decimal implements an arbitrary precision fixed-point decimal.

The zero-value of a Decimal is 0, as you would expect.

The best way to create a new Decimal is to use decimal.NewFromString, ex:

```n, err := decimal.NewFromString("-123.4567")
n.String() // output: "-123.4567"
```

To use Decimal as part of a struct:

```type Struct struct {
Number Decimal
}
```

Note: This can "only" represent numbers with a maximum of 2^31 digits after the decimal point.

### Constants ¶

This section is empty.

### Variables ¶

View Source
`var DivisionPrecision = 16`

DivisionPrecision is the number of decimal places in the result when it doesn't divide exactly.

Example:

```d1 := decimal.NewFromFloat(2).Div(decimal.NewFromFloat(3))
d1.String() // output: "0.6666666666666667"
d2 := decimal.NewFromFloat(2).Div(decimal.NewFromFloat(30000))
d2.String() // output: "0.0000666666666667"
d3 := decimal.NewFromFloat(20000).Div(decimal.NewFromFloat(3))
d3.String() // output: "6666.6666666666666667"
decimal.DivisionPrecision = 3
d4 := decimal.NewFromFloat(2).Div(decimal.NewFromFloat(3))
d4.String() // output: "0.667"
```
View Source
`var ExpMaxIterations = 1000`

ExpMaxIterations specifies the maximum number of iterations needed to calculate precise natural exponent value using ExpHullAbrham method.

View Source
`var MarshalJSONWithoutQuotes = false`

MarshalJSONWithoutQuotes should be set to true if you want the decimal to be JSON marshaled as a number, instead of as a string. WARNING: this is dangerous for decimals with many digits, since many JSON unmarshallers (ex: Javascript's) will unmarshal JSON numbers to IEEE 754 double-precision floating point numbers, which means you can potentially silently lose precision.

View Source
`var Zero = New(0, 1)`

Zero constant, to make computations faster. Zero should never be compared with == or != directly, please use decimal.Equal or decimal.Cmp instead.

### Functions ¶

#### func RescalePair ¶

`func RescalePair(d1 Decimal, d2 Decimal) (Decimal, Decimal)`

RescalePair rescales two decimals to common exponential value (minimal exp of both decimals)

### Types ¶

#### type Decimal ¶

```type Decimal struct {
// contains filtered or unexported fields
}```

Decimal represents a fixed-point decimal. It is immutable. number = value * 10 ^ exp

#### func Avg ¶

`func Avg(first Decimal, rest ...Decimal) Decimal`

Avg returns the average value of the provided first and rest Decimals

#### func Max ¶

`func Max(first Decimal, rest ...Decimal) Decimal`

Max returns the largest Decimal that was passed in the arguments.

To call this function with an array, you must do:

```Max(arr[0], arr[1:]...)
```

This makes it harder to accidentally call Max with 0 arguments.

#### func Min ¶

`func Min(first Decimal, rest ...Decimal) Decimal`

Min returns the smallest Decimal that was passed in the arguments.

To call this function with an array, you must do:

```Min(arr[0], arr[1:]...)
```

This makes it harder to accidentally call Min with 0 arguments.

#### func New ¶

`func New(value int64, exp int32) Decimal`

New returns a new fixed-point decimal, value * 10 ^ exp.

#### func NewFromBigInt ¶

`func NewFromBigInt(value *big.Int, exp int32) Decimal`

NewFromBigInt returns a new Decimal from a big.Int, value * 10 ^ exp

#### func NewFromFloat ¶

`func NewFromFloat(value float64) Decimal`

NewFromFloat converts a float64 to Decimal.

The converted number will contain the number of significant digits that can be represented in a float with reliable roundtrip. This is typically 15 digits, but may be more in some cases. See https://www.exploringbinary.com/decimal-precision-of-binary-floating-point-numbers/ for more information.

For slightly faster conversion, use NewFromFloatWithExponent where you can specify the precision in absolute terms.

NOTE: this will panic on NaN, +/-inf

#### func NewFromFloat32 ¶

`func NewFromFloat32(value float32) Decimal`

NewFromFloat32 converts a float32 to Decimal.

The converted number will contain the number of significant digits that can be represented in a float with reliable roundtrip. This is typically 6-8 digits depending on the input. See https://www.exploringbinary.com/decimal-precision-of-binary-floating-point-numbers/ for more information.

For slightly faster conversion, use NewFromFloatWithExponent where you can specify the precision in absolute terms.

NOTE: this will panic on NaN, +/-inf

#### func NewFromFloatWithExponent ¶

`func NewFromFloatWithExponent(value float64, exp int32) Decimal`

NewFromFloatWithExponent converts a float64 to Decimal, with an arbitrary number of fractional digits.

Example:

```NewFromFloatWithExponent(123.456, -2).String() // output: "123.46"
```

#### func NewFromFormattedString ¶ added in v1.5.2

`func NewFromFormattedString(value string, replRegexp *regexp.Regexp) (Decimal, error)`

NewFromFormattedString returns a new Decimal from a formatted string representation. The second argument - replRegexp, is a regular expression that is used to find characters that should be removed from given decimal string representation. All matched characters will be replaced with an empty string.

Example:

```r := regexp.MustCompile("[\$,]")
d1, err := NewFromFormattedString("\$5,125.99", r)

r2 := regexp.MustCompile("[_]")
d2, err := NewFromFormattedString("1_000_000", r2)

r3 := regexp.MustCompile("[USD\\s]")
d3, err := NewFromFormattedString("5000 USD", r3)
```

#### func NewFromInt ¶

`func NewFromInt(value int64) Decimal`

NewFromInt converts a int64 to Decimal.

Example:

```NewFromInt(123).String() // output: "123"
NewFromInt(-10).String() // output: "-10"
```

#### func NewFromInt32 ¶

`func NewFromInt32(value int32) Decimal`

NewFromInt32 converts a int32 to Decimal.

Example:

```NewFromInt(123).String() // output: "123"
NewFromInt(-10).String() // output: "-10"
```

#### func NewFromString ¶

`func NewFromString(value string) (Decimal, error)`

NewFromString returns a new Decimal from a string representation. Trailing zeroes are not trimmed.

Example:

```d, err := NewFromString("-123.45")
d2, err := NewFromString(".0001")
d3, err := NewFromString("1.47000")
```

#### func RequireFromString ¶

`func RequireFromString(value string) Decimal`

RequireFromString returns a new Decimal from a string representation or panics if NewFromString would have returned an error.

Example:

```d := RequireFromString("-123.45")
d2 := RequireFromString(".0001")
```

#### func Sum ¶

`func Sum(first Decimal, rest ...Decimal) Decimal`

Sum returns the combined total of the provided first and rest Decimals

#### func (Decimal) Abs ¶

`func (d Decimal) Abs() Decimal`

Abs returns the absolute value of the decimal.

`func (d Decimal) Add(d2 Decimal) Decimal`

#### func (Decimal) Atan ¶

`func (d Decimal) Atan() Decimal`

Atan returns the arctangent, in radians, of x.

#### func (Decimal) BigFloat ¶

`func (d Decimal) BigFloat() *big.Float`

BigFloat returns decimal as BigFloat. Be aware that casting decimal to BigFloat might cause a loss of precision.

#### func (Decimal) BigInt ¶

`func (d Decimal) BigInt() *big.Int`

BigInt returns integer component of the decimal as a BigInt.

#### func (Decimal) Ceil ¶

`func (d Decimal) Ceil() Decimal`

Ceil returns the nearest integer value greater than or equal to d.

#### func (Decimal) Cmp ¶

`func (d Decimal) Cmp(d2 Decimal) int`

Cmp compares the numbers represented by d and d2 and returns:

```-1 if d <  d2
0 if d == d2
+1 if d >  d2
```

#### func (Decimal) Coefficient ¶

`func (d Decimal) Coefficient() *big.Int`

Coefficient returns the coefficient of the decimal. It is scaled by 10^Exponent()

#### func (Decimal) CoefficientInt64 ¶ added in v1.5.2

`func (d Decimal) CoefficientInt64() int64`

CoefficientInt64 returns the coefficient of the decimal as int64. It is scaled by 10^Exponent() If coefficient cannot be represented in an int64, the result will be undefined.

#### func (Decimal) Copy ¶ added in v1.5.2

`func (d Decimal) Copy() Decimal`

Copy returns a copy of decimal with the same value and exponent, but a different pointer to value.

#### func (Decimal) Cos ¶

`func (d Decimal) Cos() Decimal`

Cos returns the cosine of the radian argument x.

#### func (Decimal) Div ¶

`func (d Decimal) Div(d2 Decimal) Decimal`

Div returns d / d2. If it doesn't divide exactly, the result will have DivisionPrecision digits after the decimal point.

#### func (Decimal) DivRound ¶

`func (d Decimal) DivRound(d2 Decimal, precision int32) Decimal`

DivRound divides and rounds to a given precision i.e. to an integer multiple of 10^(-precision)

```for a positive quotient digit 5 is rounded up, away from 0
if the quotient is negative then digit 5 is rounded down, away from 0
```

Note that precision<0 is allowed as input.

#### func (Decimal) Equal ¶

`func (d Decimal) Equal(d2 Decimal) bool`

Equal returns whether the numbers represented by d and d2 are equal.

#### func (Decimal) Equals ¶

`func (d Decimal) Equals(d2 Decimal) bool`

#### func (Decimal) ExpHullAbrham ¶ added in v1.5.2

`func (d Decimal) ExpHullAbrham(overallPrecision uint32) (Decimal, error)`

ExpHullAbrham calculates the natural exponent of decimal (e to the power of d) using Hull-Abraham algorithm. OverallPrecision argument specifies the overall precision of the result (integer part + decimal part).

ExpHullAbrham is faster than ExpTaylor for small precision values, but it is much slower for large precision values.

Example:

```NewFromFloat(26.1).ExpHullAbrham(2).String()    // output: "220000000000"
NewFromFloat(26.1).ExpHullAbrham(20).String()   // output: "216314672147.05767284"
```

#### func (Decimal) ExpTaylor ¶ added in v1.5.2

`func (d Decimal) ExpTaylor(precision int32) (Decimal, error)`

ExpTaylor calculates the natural exponent of decimal (e to the power of d) using Taylor series expansion. Precision argument specifies how precise the result must be (number of digits after decimal point). Negative precision is allowed.

ExpTaylor is much faster for large precision values than ExpHullAbrham.

Example:

```d, err := NewFromFloat(26.1).ExpTaylor(2).String()
d.String()  // output: "216314672147.06"

NewFromFloat(26.1).ExpTaylor(20).String()
d.String()  // output: "216314672147.05767284062928674083"

NewFromFloat(26.1).ExpTaylor(-10).String()
d.String()  // output: "220000000000"
```

#### func (Decimal) Exponent ¶

`func (d Decimal) Exponent() int32`

Exponent returns the exponent, or scale component of the decimal.

#### func (Decimal) Float64 ¶

`func (d Decimal) Float64() (f float64, exact bool)`

Float64 returns the nearest float64 value for d and a bool indicating whether f represents d exactly. For more details, see the documentation for big.Rat.Float64

#### func (Decimal) Floor ¶

`func (d Decimal) Floor() Decimal`

Floor returns the nearest integer value less than or equal to d.

#### func (*Decimal) GobDecode ¶

`func (d *Decimal) GobDecode(data []byte) error`

GobDecode implements the gob.GobDecoder interface for gob serialization.

#### func (Decimal) GobEncode ¶

`func (d Decimal) GobEncode() ([]byte, error)`

GobEncode implements the gob.GobEncoder interface for gob serialization.

#### func (Decimal) GreaterThan ¶

`func (d Decimal) GreaterThan(d2 Decimal) bool`

GreaterThan (GT) returns true when d is greater than d2.

#### func (Decimal) GreaterThanOrEqual ¶

`func (d Decimal) GreaterThanOrEqual(d2 Decimal) bool`

GreaterThanOrEqual (GTE) returns true when d is greater than or equal to d2.

#### func (Decimal) InexactFloat64 ¶ added in v1.5.2

`func (d Decimal) InexactFloat64() float64`

InexactFloat64 returns the nearest float64 value for d. It doesn't indicate if the returned value represents d exactly.

#### func (Decimal) IntPart ¶

`func (d Decimal) IntPart() int64`

IntPart returns the integer component of the decimal.

#### func (Decimal) IsInteger ¶ added in v1.5.2

`func (d Decimal) IsInteger() bool`

IsInteger returns true when decimal can be represented as an integer value, otherwise, it returns false.

#### func (Decimal) IsNegative ¶

`func (d Decimal) IsNegative() bool`

IsNegative return

```true if d < 0
false if d == 0
false if d > 0
```

#### func (Decimal) IsPositive ¶

`func (d Decimal) IsPositive() bool`

IsPositive return

```true if d > 0
false if d == 0
false if d < 0
```

#### func (Decimal) IsZero ¶

`func (d Decimal) IsZero() bool`

IsZero return

```true if d == 0
false if d > 0
false if d < 0
```

#### func (Decimal) LessThan ¶

`func (d Decimal) LessThan(d2 Decimal) bool`

LessThan (LT) returns true when d is less than d2.

#### func (Decimal) LessThanOrEqual ¶

`func (d Decimal) LessThanOrEqual(d2 Decimal) bool`

LessThanOrEqual (LTE) returns true when d is less than or equal to d2.

#### func (Decimal) MarshalBinary ¶

`func (d Decimal) MarshalBinary() (data []byte, err error)`

MarshalBinary implements the encoding.BinaryMarshaler interface.

#### func (Decimal) MarshalJSON ¶

`func (d Decimal) MarshalJSON() ([]byte, error)`

MarshalJSON implements the json.Marshaler interface.

#### func (Decimal) MarshalText ¶

`func (d Decimal) MarshalText() (text []byte, err error)`

MarshalText implements the encoding.TextMarshaler interface for XML serialization.

#### func (Decimal) Mod ¶

`func (d Decimal) Mod(d2 Decimal) Decimal`

Mod returns d % d2.

#### func (Decimal) Mul ¶

`func (d Decimal) Mul(d2 Decimal) Decimal`

Mul returns d * d2.

#### func (Decimal) Neg ¶

`func (d Decimal) Neg() Decimal`

Neg returns -d.

#### func (Decimal) NumDigits ¶ added in v1.5.2

`func (d Decimal) NumDigits() int`

NumDigits returns the number of digits of the decimal coefficient (d.Value) Note: Current implementation is extremely slow for large decimals and/or decimals with large fractional part

#### func (Decimal) Pow ¶

`func (d Decimal) Pow(d2 Decimal) Decimal`

Pow returns d to the power d2

#### func (Decimal) QuoRem ¶

`func (d Decimal) QuoRem(d2 Decimal, precision int32) (Decimal, Decimal)`

QuoRem does division with remainder d.QuoRem(d2,precision) returns quotient q and remainder r such that

```d = d2 * q + r, q an integer multiple of 10^(-precision)
0 <= r < abs(d2) * 10 ^(-precision) if d>=0
0 >= r > -abs(d2) * 10 ^(-precision) if d<0
```

Note that precision<0 is allowed as input.

#### func (Decimal) Rat ¶

`func (d Decimal) Rat() *big.Rat`

Rat returns a rational number representation of the decimal.

#### func (Decimal) Round ¶

`func (d Decimal) Round(places int32) Decimal`

Round rounds the decimal to places decimal places. If places < 0, it will round the integer part to the nearest 10^(-places).

Example:

```NewFromFloat(5.45).Round(1).String() // output: "5.5"
NewFromFloat(545).Round(-1).String() // output: "550"
```

#### func (Decimal) RoundBank ¶

`func (d Decimal) RoundBank(places int32) Decimal`

RoundBank rounds the decimal to places decimal places. If the final digit to round is equidistant from the nearest two integers the rounded value is taken as the even number

If places < 0, it will round the integer part to the nearest 10^(-places).

Examples:

```NewFromFloat(5.45).RoundBank(1).String() // output: "5.4"
NewFromFloat(545).RoundBank(-1).String() // output: "540"
NewFromFloat(5.46).RoundBank(1).String() // output: "5.5"
NewFromFloat(546).RoundBank(-1).String() // output: "550"
NewFromFloat(5.55).RoundBank(1).String() // output: "5.6"
NewFromFloat(555).RoundBank(-1).String() // output: "560"
```

#### func (Decimal) RoundCash ¶

`func (d Decimal) RoundCash(interval uint8) Decimal`

RoundCash aka Cash/Penny/öre rounding rounds decimal to a specific interval. The amount payable for a cash transaction is rounded to the nearest multiple of the minimum currency unit available. The following intervals are available: 5, 10, 25, 50 and 100; any other number throws a panic.

```  5:   5 cent rounding 3.43 => 3.45
10:  10 cent rounding 3.45 => 3.50 (5 gets rounded 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
```

For more details: https://en.wikipedia.org/wiki/Cash_rounding

#### func (Decimal) RoundCeil ¶ added in v1.5.2

`func (d Decimal) RoundCeil(places int32) Decimal`

RoundCeil rounds the decimal towards +infinity.

Example:

```NewFromFloat(545).RoundCeil(-2).String()   // output: "600"
NewFromFloat(500).RoundCeil(-2).String()   // output: "500"
NewFromFloat(1.1001).RoundCeil(2).String() // output: "1.11"
NewFromFloat(-1.454).RoundCeil(1).String() // output: "-1.5"
```

#### func (Decimal) RoundDown ¶ added in v1.5.2

`func (d Decimal) RoundDown(places int32) Decimal`

RoundDown rounds the decimal towards zero.

Example:

```NewFromFloat(545).RoundDown(-2).String()   // output: "500"
NewFromFloat(-500).RoundDown(-2).String()   // output: "-500"
NewFromFloat(1.1001).RoundDown(2).String() // output: "1.1"
NewFromFloat(-1.454).RoundDown(1).String() // output: "-1.5"
```

#### func (Decimal) RoundFloor ¶ added in v1.5.2

`func (d Decimal) RoundFloor(places int32) Decimal`

RoundFloor rounds the decimal towards -infinity.

Example:

```NewFromFloat(545).RoundFloor(-2).String()   // output: "500"
NewFromFloat(-500).RoundFloor(-2).String()   // output: "-500"
NewFromFloat(1.1001).RoundFloor(2).String() // output: "1.1"
NewFromFloat(-1.454).RoundFloor(1).String() // output: "-1.4"
```

#### func (Decimal) RoundUp ¶ added in v1.5.2

`func (d Decimal) RoundUp(places int32) Decimal`

RoundUp rounds the decimal away from zero.

Example:

```NewFromFloat(545).RoundUp(-2).String()   // output: "600"
NewFromFloat(500).RoundUp(-2).String()   // output: "500"
NewFromFloat(1.1001).RoundUp(2).String() // output: "1.11"
NewFromFloat(-1.454).RoundUp(1).String() // output: "-1.4"
```

#### func (*Decimal) Scan ¶

`func (d *Decimal) Scan(value interface{}) error`

Scan implements the sql.Scanner interface for database deserialization.

#### func (Decimal) Shift ¶

`func (d Decimal) Shift(shift int32) Decimal`

Shift shifts the decimal in base 10. It shifts left when shift is positive and right if shift is negative. In simpler terms, the given value for shift is added to the exponent of the decimal.

#### func (Decimal) Sign ¶

`func (d Decimal) Sign() int`

Sign returns:

```-1 if d <  0
0 if d == 0
+1 if d >  0
```

#### func (Decimal) Sin ¶

`func (d Decimal) Sin() Decimal`

Sin returns the sine of the radian argument x.

#### func (Decimal) String ¶

`func (d Decimal) String() string`

String returns the string representation of the decimal with the fixed point.

Example:

```d := New(-12345, -3)
println(d.String())
```

Output:

```-12.345
```

#### func (Decimal) StringFixed ¶

`func (d Decimal) StringFixed(places int32) string`

StringFixed returns a rounded fixed-point string with places digits after the decimal point.

Example:

```NewFromFloat(0).StringFixed(2) // output: "0.00"
NewFromFloat(0).StringFixed(0) // output: "0"
NewFromFloat(5.45).StringFixed(0) // output: "5"
NewFromFloat(5.45).StringFixed(1) // output: "5.5"
NewFromFloat(5.45).StringFixed(2) // output: "5.45"
NewFromFloat(5.45).StringFixed(3) // output: "5.450"
NewFromFloat(545).StringFixed(-1) // output: "550"
```

#### func (Decimal) StringFixedBank ¶

`func (d Decimal) StringFixedBank(places int32) string`

StringFixedBank returns a banker rounded fixed-point string with places digits after the decimal point.

Example:

```NewFromFloat(0).StringFixedBank(2) // output: "0.00"
NewFromFloat(0).StringFixedBank(0) // output: "0"
NewFromFloat(5.45).StringFixedBank(0) // output: "5"
NewFromFloat(5.45).StringFixedBank(1) // output: "5.4"
NewFromFloat(5.45).StringFixedBank(2) // output: "5.45"
NewFromFloat(5.45).StringFixedBank(3) // output: "5.450"
NewFromFloat(545).StringFixedBank(-1) // output: "540"
```

#### func (Decimal) StringFixedCash ¶

`func (d Decimal) StringFixedCash(interval uint8) string`

StringFixedCash returns a Swedish/Cash rounded fixed-point string. For more details see the documentation at function RoundCash.

#### func (Decimal) StringScaled ¶

`func (d Decimal) StringScaled(exp int32) string`

StringScaled first scales the decimal then calls .String() on it. NOTE: buggy, unintuitive, and DEPRECATED! Use StringFixed instead.

#### func (Decimal) Sub ¶

`func (d Decimal) Sub(d2 Decimal) Decimal`

Sub returns d - d2.

#### func (Decimal) Tan ¶

`func (d Decimal) Tan() Decimal`

Tan returns the tangent of the radian argument x.

#### func (Decimal) Truncate ¶

`func (d Decimal) Truncate(precision int32) Decimal`

Truncate truncates off digits from the number, without rounding.

NOTE: precision is the last digit that will not be truncated (must be >= 0).

Example:

```decimal.NewFromString("123.456").Truncate(2).String() // "123.45"
```

#### func (*Decimal) UnmarshalBinary ¶

`func (d *Decimal) UnmarshalBinary(data []byte) error`

UnmarshalBinary implements the encoding.BinaryUnmarshaler interface. As a string representation is already used when encoding to text, this method stores that string as []byte

#### func (*Decimal) UnmarshalJSON ¶

`func (d *Decimal) UnmarshalJSON(decimalBytes []byte) error`

UnmarshalJSON implements the json.Unmarshaler interface.

#### func (*Decimal) UnmarshalText ¶

`func (d *Decimal) UnmarshalText(text []byte) error`

UnmarshalText implements the encoding.TextUnmarshaler interface for XML deserialization.

#### func (Decimal) Value ¶

`func (d Decimal) Value() (driver.Value, error)`

Value implements the driver.Valuer interface for database serialization.

#### type NullDecimal ¶

```type NullDecimal struct {
Decimal Decimal
Valid   bool
}```

NullDecimal represents a nullable decimal with compatibility for scanning null values from the database.

#### func NewNullDecimal ¶ added in v1.5.2

`func NewNullDecimal(d Decimal) NullDecimal`

#### func (NullDecimal) MarshalJSON ¶

`func (d NullDecimal) MarshalJSON() ([]byte, error)`

MarshalJSON implements the json.Marshaler interface.

#### func (NullDecimal) MarshalText ¶ added in v1.5.2

`func (d NullDecimal) MarshalText() (text []byte, err error)`

MarshalText implements the encoding.TextMarshaler interface for XML serialization.

#### func (*NullDecimal) Scan ¶

`func (d *NullDecimal) Scan(value interface{}) error`

Scan implements the sql.Scanner interface for database deserialization.

#### func (*NullDecimal) UnmarshalJSON ¶

`func (d *NullDecimal) UnmarshalJSON(decimalBytes []byte) error`

UnmarshalJSON implements the json.Unmarshaler interface.

#### func (*NullDecimal) UnmarshalText ¶ added in v1.5.2

`func (d *NullDecimal) UnmarshalText(text []byte) error`

UnmarshalText implements the encoding.TextUnmarshaler interface for XML deserialization

#### func (NullDecimal) Value ¶

`func (d NullDecimal) Value() (driver.Value, error)`

Value implements the driver.Valuer interface for database serialization.