accounting - money and currency formatting for golang

accounting is a library for money and currency formatting. (inspired by accounting.js)

Quick Start

go get github.com/leekchan/accounting

example.go

package main

import (
    "fmt"
    "math/big"

    "github.com/shopspring/decimal"
    "github.com/leekchan/accounting"
)

func main() {
    ac := accounting.Accounting{Symbol: "$", Precision: 2}
    fmt.Println(ac.FormatMoney(123456789.213123))                       // "$123,456,789.21"
    fmt.Println(ac.FormatMoney(12345678))                               // "$12,345,678.00"
    fmt.Println(ac.FormatMoney(big.NewRat(77777777, 3)))                // "$25,925,925.67"
    fmt.Println(ac.FormatMoney(big.NewRat(-77777777, 3)))               // "-$25,925,925.67"
    fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(123456789.213123))) // "$123,456,789.21"
    fmt.Println(ac.FormatMoneyDecimal(decimal.New(123456789.213123, 0))) // "$123,456,789.21"

    ac = accounting.Accounting{Symbol: "€", Precision: 2, Thousand: ".", Decimal: ","}
    fmt.Println(ac.FormatMoney(4999.99))  // "€4.999,99"

    // Or retrieve currency info from Locale struct
    lc := LocaleInfo["USD"]
    ac = accounting.Accounting{Symbol: lc.ComSymbol, Precision: 2, Thousand: lc.ThouSep, Decimal: lc.DecSep}
    fmt.Println(ac.FormatMoney(500000)) // "$500,000.00"

    ac = accounting.Accounting{Symbol: "£ ", Precision: 0}
    fmt.Println(ac.FormatMoney(500000)) // "£ 500,000"

    ac = accounting.Accounting{Symbol: "GBP", Precision: 0,
        Format: "%s %v", FormatNegative: "%s (%v)", FormatZero: "%s --"}
    fmt.Println(ac.FormatMoney(1000000)) // "GBP 1,000,000"
    fmt.Println(ac.FormatMoney(-5000))   // "GBP (5,000)"
    fmt.Println(ac.FormatMoney(0))       // "GBP --"

    ac = accounting.DefaultAccounting("GBP", 2)
    fmt.Println(ac.FormatMoney(1000000)) // "GBP 1,000,000"
    fmt.Println(ac.FormatMoney(-5000))   // "GBP (5,000)"
    fmt.Println(ac.FormatMoney(0))       // "GBP --"

    ac = accounting.NewAccounting("GBP", 2, ",", ".", "%s %v", "%s (%v)", "%s --")
    fmt.Println(ac.FormatMoney(1000000)) // "GBP 1,000,000"
    fmt.Println(ac.FormatMoney(-5000))   // "GBP (5,000)"
    fmt.Println(ac.FormatMoney(0))       // "GBP --"
}

Caution

Please do not use float64 to count money. Floats can have errors when you perform operations on them. Using big.Rat (< Go 1.5) or big.Float (>= Go 1.5) is highly recommended. (accounting supports float64, but it is just for convenience.)

• FormatMoneyBigFloat(value *big.Float) string
• FormatMoneyBigRat(value *big.Rat) string

Initialization

Accounting struct

type Accounting struct {
    Symbol         string // currency symbol (required)
    Precision      int    // currency precision (decimal places) (optional / default: 0)
    Thousand       string // thousand separator (optional / default: ,)
    Decimal        string // decimal separator (optional / default: .)
    Format         string // simple format string allows control of symbol position (%v = value, %s = symbol) (default: %s%v)
    FormatNegative string // format string for negative values (optional / default: strings.Replace(strings.Replace(accounting.Format, "-", "", -1), "%v", "-%v", -1))
    FormatZero     string // format string for zero values (optional / default: Format)
}

Examples:

# Via functions
ac := accounting.DefaultAccounting("$", 2)
ac := accounting.NewAccounting("$", 2, ",", ".", "%s %v", "%s (%v)", "%s --")

# Via Accounting struct
ac := accounting.Accounting{Symbol: "$", Precision: 2}

ac = accounting.Accounting{Symbol: "€", Precision: 2, Thousand: ".", Decimal: ","}

ac = accounting.Accounting{Symbol: "GBP", Precision: 0,
        Format: "%s %v", FormatNegative: "%s (%v)", FormatZero: "%s --"}

SetThousandSeparator(str string)

SetThousandSeparator sets the separator for the thousands separation

SetDecimalSeparator(str string)

SetDecimalSeparator sets the separator for the decimal separation

SetFormat(str string)

SetFormat sets the Format default: %s%v (%s=Symbol;%v=Value)

SetFormatNegative(str string)

SetFormatNegative sets the Format for negative values default: -%s%v (%s=Symbol;%v=Value)

SetFormatZero(str string)

SetFormatZero sets the Format for zero values default: %s%v (%s=Symbol;%v=Value)

Locale struct

type Locale struct {
    Name           string // currency name
    FractionLength int    // default decimal length
    ThouSep        string // thousands seperator
    DecSep         string // decimal seperator
    SpaceSep       string // space seperator
    UTFSymbol      string // UTF symbol
    HTMLSymbol     string // HTML symbol
    ComSymbol      string // Common symbol
    Pre            bool   // symbol before or after currency
}

Example:

// LocaleInfo map[string]Locale

var lc Locale
if val, ok := LocaleInfo["USD"]; ok {
    lc = val
} else {
    panic("No Locale Info Found")
}

fmt.Println(lc.Name) // "US Dollar"
fmt.Println(lc.FractionLength) // 2
fmt.Println(lc.ThouSep) // ","
fmt.Println(lc.DecSep) // "."
fmt.Println(lc.SpaceSep) // ""
fmt.Println(lc.UTFSymbol) // "0024"
fmt.Println(lc.HTMLSymbol) // "&#x0024"
fmt.Println(lc.ComSymbol) // "$"
fmt.Println(lc.Pre) // true

There are currently 181 currencies supported in LocaleInfo

FormatMoney(value interface{}) string

FormatMoney is a function for formatting numbers as money values, with customisable currency symbol, precision (decimal places), and thousand/decimal separators.

FormatMoney supports various types of value by runtime reflection. If you don't need runtime type evaluation, please refer to FormatMoneyInt, FormatMoneyBigRat, FormatMoneyBigRat, or FormatMoneyFloat64.

• supported value types : int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, float32, float64, *big.Rat

Examples:

ac := accounting.Accounting{Symbol: "$", Precision: 2}
fmt.Println(ac.FormatMoney(123456789.213123))         // "$123,456,789.21"
fmt.Println(ac.FormatMoney(12345678))                 // "$12,345,678.00"
fmt.Println(ac.FormatMoney(big.NewRat(77777777, 3)))  // "$25,925,925.67"
fmt.Println(ac.FormatMoney(big.NewRat(-77777777, 3))) // "-$25,925,925.67"

ac = accounting.Accounting{Symbol: "€", Precision: 2, Thousand: ".", Decimal: ","}
fmt.Println(ac.FormatMoney(4999.99))  // "€4.999,99"

ac = accounting.Accounting{Symbol: "£ ", Precision: 0}
fmt.Println(ac.FormatMoney(500000)) // "£ 500,000"

ac = accounting.Accounting{Symbol: "GBP", Precision: 0,
    Format: "%s %v", FormatNegative: "%s (%v)", FormatZero: "%s --"}
fmt.Println(ac.FormatMoney(1000000)) // "GBP 1,000,000"
fmt.Println(ac.FormatMoney(-5000))   // "GBP (5,000)"
fmt.Println(ac.FormatMoney(0))       // "GBP --"

FormatMoneyBigFloat(value *big.Float) string

(>= Go 1.5)

FormatMoneyBigFloat only supports *big.Float value. It is faster than FormatMoney, because it does not do any runtime type evaluation.

Examples:

ac = accounting.Accounting{Symbol: "$", Precision: 2}
fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(123456789.213123))) // "$123,456,789.21"
fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(12345678)))         // "$12,345,678.00"

ac = accounting.Accounting{Symbol: "€", Precision: 2, Thousand: ".", Decimal: ","}
fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(4999.99)))  // "€4.999,99"

ac = accounting.Accounting{Symbol: "£ ", Precision: 0}
fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(500000))) // "£ 500,000"

ac = accounting.Accounting{Symbol: "GBP", Precision: 0,
    Format: "%s %v", FormatNegative: "%s (%v)", FormatZero: "%s --"}
fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(1000000))) // "GBP 1,000,000"
fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(-5000)))   // "GBP (5,000)"
fmt.Println(ac.FormatMoneyBigFloat(big.NewFloat(0)))       // "GBP --"

FormatMoneyInt(value int) string

FormatMoneyInt only supports int value. It is faster than FormatMoney, because it does not do any runtime type evaluation.

Examples:

ac = accounting.Accounting{Symbol: "$", Precision: 2}
fmt.Println(ac.FormatMoneyInt(12345678)) // "$12,345,678.00"

ac = accounting.Accounting{Symbol: "€", Precision: 2, Thousand: ".", Decimal: ","}
fmt.Println(ac.FormatMoneyInt(4999))  // "€4.999,00"

ac = accounting.Accounting{Symbol: "£ ", Precision: 0}
fmt.Println(ac.FormatMoneyInt(500000)) // "£ 500,000"

ac = accounting.Accounting{Symbol: "GBP", Precision: 0,
    Format: "%s %v", FormatNegative: "%s (%v)", FormatZero: "%s --"}
fmt.Println(ac.FormatMoneyInt(1000000)) // "GBP 1,000,000"
fmt.Println(ac.FormatMoneyInt(-5000))   // "GBP (5,000)"
fmt.Println(ac.FormatMoneyInt(0))       // "GBP --"

FormatMoneyBigRat(value *big.Rat) string

FormatMoneyBigRat only supports *big.Rat value. It is faster than FormatMoney, because it does not do any runtime type evaluation.

Examples:

ac = accounting.Accounting{Symbol: "$", Precision: 2}
fmt.Println(ac.FormatMoneyBigRat(big.NewRat(77777777, 3)))  // "$25,925,925.67"
fmt.Println(ac.FormatMoneyBigRat(big.NewRat(-77777777, 3))) // "-$25,925,925.67"

ac = accounting.Accounting{Symbol: "€", Precision: 2, Thousand: ".", Decimal: ","}
fmt.Println(ac.FormatMoneyBigRat(big.NewRat(77777777, 3)))  // "€25.925.925,67"

ac = accounting.Accounting{Symbol: "£ ", Precision: 0}
fmt.Println(ac.FormatMoneyBigRat(big.NewRat(77777777, 3)))  // "£ 25,925,926"

ac = accounting.Accounting{Symbol: "GBP", Precision: 0,
    Format: "%s %v", FormatNegative: "%s (%v)", FormatZero: "%s --"}
fmt.Println(ac.FormatMoneyBigRat(big.NewRat(77777777, 3)))  // "GBP 25,925,926"
fmt.Println(ac.FormatMoneyBigRat(big.NewRat(-77777777, 3))) // "GBP (25,925,926)"
fmt.Println(ac.FormatMoneyBigRat(big.NewRat(0, 3)))         // "GBP --"

FormatMoneyFloat64(value float64) string

FormatMoneyFloat64 only supports float64 value. It is faster than FormatMoney, because it does not do any runtime type evaluation.

Examples:

ac = accounting.Accounting{Symbol: "$", Precision: 2}
fmt.Println(ac.FormatMoneyFloat64(123456789.213123)) // "$123,456,789.21"
fmt.Println(ac.FormatMoneyFloat64(12345678))         // "$12,345,678.00"

ac = accounting.Accounting{Symbol: "€", Precision: 2, Thousand: ".", Decimal: ","}
fmt.Println(ac.FormatMoneyFloat64(4999.99))  // "€4.999,99"

ac = accounting.Accounting{Symbol: "£ ", Precision: 0}
fmt.Println(ac.FormatMoneyFloat64(500000)) // "£ 500,000"

ac = accounting.Accounting{Symbol: "GBP", Precision: 0,
    Format: "%s %v", FormatNegative: "%s (%v)", FormatZero: "%s --"}
fmt.Println(ac.FormatMoneyFloat64(1000000)) // "GBP 1,000,000"
fmt.Println(ac.FormatMoneyFloat64(-5000))   // "GBP (5,000)"
fmt.Println(ac.FormatMoneyFloat64(0))       // "GBP --"

FormatNumber(value interface{}, precision int, thousand string, decimal string) string

FormatNumber is a base function of the library which formats a number with custom precision and separators.

FormatNumber supports various types of value by runtime reflection. If you don't need runtime type evaluation, please refer to FormatNumberInt, FormatNumberBigRat, or FormatNumberFloat64.

• supported value types : int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, float32, float64, *big.Rat

Examples:

fmt.Println(accounting.FormatNumber(123456789.213123, 3, ",", ".")) // "123,456,789.213"
fmt.Println(accounting.FormatNumber(1000000, 3, " ", ","))          // "1 000 000,000"

FormatNumberBigFloat(value *big.Float, precision int, thousand string, decimal string) string

(>= Go 1.5)

FormatNumberBigFloat only supports *big.Float value. It is faster than FormatNumber, because it does not do any runtime type evaluation.

Examples:

fmt.Println(accounting.FormatNumberBigFloat(big.NewFloat(123456789.213123), 3, ",", ".")) // "123,456,789.213"

FormatNumberInt(value int, precision int, thousand string, decimal string) string

FormatNumberInt only supports int value. It is faster than FormatNumber, because it does not do any runtime type evaluation.

Examples:

fmt.Println(accounting.FormatNumberInt(123456789, 3, ",", ".")) // "123,456,789.000"

FormatNumberBigRat(value *big.Rat, precision int, thousand string, decimal string) string

FormatNumberBigRat only supports *big.Rat value. It is faster than FormatNumber, because it does not do any runtime type evaluation.

Examples:

fmt.Println(accounting.FormatNumberBigRat(big.NewRat(77777777, 3), 3, ",", ".")) // "25,925,925.667"

FormatNumberFloat64(value float64, precision int, thousand string, decimal string) string

FormatNumberFloat64 only supports float64 value. It is faster than FormatNumber, because it does not do any runtime type evaluation.

Examples:

fmt.Println(accounting.FormatNumberFloat64(123456789.213123, 3, ",", ".")) // "123,456,789.213"

FormatNumberDecimal(value decimal.Decimal, precision int, thousand string, decimal string) string

FormatNumberDecimal only supports decimal.Decimal value. It is faster than FormatNumber, because it does not do any runtime type evaluation.

Examples:

import "github.com/shopspring/decimal"
fmt.Println(accounting.FormatNumberBigDecimal(apd.New(apd.New(4999999, -3), 3, ",", ".")) // "4,999.999"

FormatNumberBigDecimal(value apd.Decimal, precision int, thousand string, decimal string) string

FormatNumberDecimal only supports apd.Decimal value. It is faster than FormatNumber, because it does not do any runtime type evaluation.

Examples:

import "github.com/cockroachdb/apd"
fmt.Println(accounting.FormatNumberDecimal(decimal.New(123456789.213123,3), 3, ",", ".")) // "123,456,789.213"

UnformatNumber(number string, precision int, currency string) string

UnformatNumber is the inverse of FormatNumber. It strips out all currency formatting and returns the number with a point for the decimal seperator.

Examples:

fmt.Println(accounting.UnformatNumber("$45,000.50", 2, "USD")) // "45000.50"
fmt.Println(accounting.UnformatNumber("EUR 12.500,3474", 3, "EUR")) // "12500.347"