strconv

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原文：https://pkg.go.dev/strconv@go1.23.0

Package strconv implements conversions to and from string representations of basic data types.

​ strconv包实现了基本数据类型的字符串表示与其相互转换的功能。

数字转换 Numeric Conversions

The most common numeric conversions are Atoi (string to int) and Itoa (int to string).

​ 最常见的数字转换是Atoi(字符串到整数)和Itoa(整数到字符串)。

​ 函数名Atoi是将字符串转换为整数的缩写，其中A代表ASCII字符集，即该函数只能处理使用ASCII字符集表示的数字字符，而不能处理使用其他字符集表示的数字字符。toi则是to int的缩写，表示将字符串转换为整数。因此，Atoi函数名的含义为将使用ASCII字符集表示的字符串转换为整数。

i, err := strconv.Atoi("-42")
s := strconv.Itoa(-42)

These assume decimal and the Go int type.

​ 这些假设十进制和Go int类型。

ParseBool, ParseFloat, ParseInt, and ParseUint convert strings to values:

​ ParseBool函数、ParseFloat函数、ParseInt函数和ParseUint函数将字符串转换为相应的数值：

b, err := strconv.ParseBool("true")
f, err := strconv.ParseFloat("3.1415", 64)
i, err := strconv.ParseInt("-42", 10, 64)
u, err := strconv.ParseUint("42", 10, 64)

The parse functions return the widest type (float64, int64, and uint64), but if the size argument specifies a narrower width the result can be converted to that narrower type without data loss:

​ 解析函数返回最宽的类型(float64、int64和uint64)，但如果size参数指定了更窄的宽度，则结果可以转换为该更窄的类型而不会丢失数据：

s := "2147483647" // biggest int32 // 最大的int32
i64, err := strconv.ParseInt(s, 10, 32)
...
i := int32(i64)

FormatBool, FormatFloat, FormatInt, and FormatUint convert values to strings:

​ FormatBool函数、FormatFloat函数、FormatInt函数和FormatUint函数将值转换为字符串：

s := strconv.FormatBool(true)
s := strconv.FormatFloat(3.1415, 'E', -1, 64)
s := strconv.FormatInt(-42, 16)
s := strconv.FormatUint(42, 16)

AppendBool, AppendFloat, AppendInt, and AppendUint are similar but append the formatted value to a destination slice.

​ AppendBool函数、AppendFloat函数、AppendInt函数和AppendUint函数类似，但将格式化的值附加到目标切片。

字符串转换 String Conversions

Quote and QuoteToASCII convert strings to quoted Go string literals. The latter guarantees that the result is an ASCII string, by escaping any non-ASCII Unicode with \u:

​ Quote函数和QuoteToASCII函数将字符串转换为带引号的Go字符串文字。后者通过使用\u转义任何非ASCII Unicode来保证结果是ASCII字符串：

q := strconv.Quote("Hello, 世界")
q := strconv.QuoteToASCII("Hello, 世界")

QuoteRune and QuoteRuneToASCII are similar but accept runes and return quoted Go rune literals.

​ QuoteRune函数和QuoteRuneToASCII函数类似，但接受符文并返回带引号的Go符文文字。

Unquote and UnquoteChar unquote Go string and rune literals.

​ Unquote函数和UnquoteChar函数取消引用Go字符串和符文文字。

常量

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const IntSize = intSize

IntSize is the size in bits of an int or uint value.

​ IntSize 是 int 或 uint 值的位数大小。

变量

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var ErrRange = errors.New("value out of range")

ErrRange indicates that a value is out of range for the target type.

​ ErrRange 表示该值超出目标类型的范围。

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var ErrSyntax = errors.New("invalid syntax")

ErrSyntax indicates that a value does not have the right syntax for the target type.

​ ErrSyntax 表示该值对于目标类型来说语法不正确。

函数

func AppendBool

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func AppendBool(dst []byte, b bool) []byte

AppendBool appends “true” or “false”, according to the value of b, to dst and returns the extended buffer.

​ AppendBool函数根据 b 的值将 “true” 或 “false” 追加到 dst 中并返回扩展后的缓冲区。

AppendBool Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	b := []byte("bool:")
	b = strconv.AppendBool(b, true)
	fmt.Println(string(b))

}
Output:

bool:true

func AppendFloat

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func AppendFloat(dst []byte, f float64, fmt byte, prec, bitSize int) []byte

AppendFloat appends the string form of the floating-point number f, as generated by FormatFloat, to dst and returns the extended buffer.

​ AppendFloat函数将浮点数 f 的字符串形式(由 FormatFloat 生成)追加到 dst 中并返回扩展后的缓冲区。

AppendFloat Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	b32 := []byte("float32:")
	b32 = strconv.AppendFloat(b32, 3.1415926535, 'E', -1, 32)
	fmt.Println(string(b32))

	b64 := []byte("float64:")
	b64 = strconv.AppendFloat(b64, 3.1415926535, 'E', -1, 64)
	fmt.Println(string(b64))

}
Output:

float32:3.1415927E+00
float64:3.1415926535E+00

func AppendInt

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func AppendInt(dst []byte, i int64, base int) []byte

AppendInt appends the string form of the integer i, as generated by FormatInt, to dst and returns the extended buffer.

​ AppendInt函数将整数 i 的字符串形式(由 FormatInt函数 生成)追加到 dst 中并返回扩展后的缓冲区。

AppendInt Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	b10 := []byte("int (base 10):")
	b10 = strconv.AppendInt(b10, -42, 10)
	fmt.Println(string(b10))

	b16 := []byte("int (base 16):")
	b16 = strconv.AppendInt(b16, -42, 16)
	fmt.Println(string(b16))

}
Output:

int (base 10):-42
int (base 16):-2a

func AppendQuote

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func AppendQuote(dst []byte, s string) []byte

AppendQuote appends a double-quoted Go string literal representing s, as generated by Quote, to dst and returns the extended buffer.

​ AppendQuote函数将表示 s 的双引号 Go 字符串文字(由 Quote函数 生成)追加到 dst 中并返回扩展后的缓冲区。

AppendQuote Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	b := []byte("quote:")
	b = strconv.AppendQuote(b, `"Fran & Freddie's Diner"`)
	fmt.Println(string(b))

}
Output:

quote:"\"Fran & Freddie's Diner\""

func AppendQuoteRune

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func AppendQuoteRune(dst []byte, r rune) []byte

AppendQuoteRune appends a single-quoted Go character literal representing the rune, as generated by QuoteRune, to dst and returns the extended buffer.

​ AppendQuoteRune函数将表示符文的单引号 Go 字符文字(由 QuoteRune函数 生成)追加到 dst 中并返回扩展后的缓冲区。

AppendQuoteRune Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	b := []byte("rune:")
	b = strconv.AppendQuoteRune(b, '☺')
	fmt.Println(string(b))

}
Output:

rune:'☺'

func AppendQuoteRuneToASCII

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func AppendQuoteRuneToASCII(dst []byte, r rune) []byte

AppendQuoteRuneToASCII appends a single-quoted Go character literal representing the rune, as generated by QuoteRuneToASCII, to dst and returns the extended buffer.

​ AppendQuoteRuneToASCII函数将表示rune的单引号Go字符文本(由QuoteRuneToASCII生成)附加到dst并返回扩展的缓冲区。

AppendQuoteRuneToASCII Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	b := []byte("rune (ascii):")
	b = strconv.AppendQuoteRuneToASCII(b, '☺')
	fmt.Println(string(b))

}
Output:

rune (ascii):'\u263a'

func AppendQuoteRuneToGraphic <- go1.6

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func AppendQuoteRuneToGraphic(dst []byte, r rune) []byte

AppendQuoteRuneToGraphic appends a single-quoted Go character literal representing the rune, as generated by QuoteRuneToGraphic, to dst and returns the extended buffer.

​ AppendQuoteRuneToGraphic函数将表示rune的单引号Go字符文本(由QuoteRuneToGraphic函数生成)附加到dst并返回扩展的缓冲区。

func AppendQuoteToASCII

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func AppendQuoteToASCII(dst []byte, s string) []byte

AppendQuoteToASCII appends a double-quoted Go string literal representing s, as generated by QuoteToASCII, to dst and returns the extended buffer.

​ AppendQuoteToASCII函数将表示s的双引号Go字符串文本(由QuoteToASCII函数生成)附加到dst并返回扩展的缓冲区。

AppendQuoteToASCII Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	b := []byte("quote (ascii):")
	b = strconv.AppendQuoteToASCII(b, `"Fran & Freddie's Diner"`)
	fmt.Println(string(b))

}
Output:

quote (ascii):"\"Fran & Freddie's Diner\""

func AppendQuoteToGraphic <- go1.6

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func AppendQuoteToGraphic(dst []byte, s string) []byte

AppendQuoteToGraphic appends a double-quoted Go string literal representing s, as generated by QuoteToGraphic, to dst and returns the extended buffer.

​ AppendQuoteToGraphic函数将表示s的双引号Go字符串文本(由QuoteToGraphic函数生成)附加到dst并返回扩展的缓冲区。

func AppendUint

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func AppendUint(dst []byte, i uint64, base int) []byte

AppendUint appends the string form of the unsigned integer i, as generated by FormatUint, to dst and returns the extended buffer.

​ AppendUint函数将生成的无符号整数i的字符串形式(由FormatUint函数生成)附加到dst并返回扩展的缓冲区。

AppendUint Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	b10 := []byte("uint (base 10):")
	b10 = strconv.AppendUint(b10, 42, 10)
	fmt.Println(string(b10))

	b16 := []byte("uint (base 16):")
	b16 = strconv.AppendUint(b16, 42, 16)
	fmt.Println(string(b16))

}
Output:

uint (base 10):42
uint (base 16):2a

func Atoi

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func Atoi(s string) (int, error)

Atoi is equivalent to ParseInt(s, 10, 0), converted to type int.

​ Atoi函数等价于ParseInt(s，10，0)，转换为int类型。

Atoi Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	v := "10"
	if s, err := strconv.Atoi(v); err == nil {
		fmt.Printf("%T, %v", s, s)
	}

}
Output:

int, 10

func CanBackquote

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func CanBackquote(s string) bool

CanBackquote reports whether the string s can be represented unchanged as a single-line backquoted string without control characters other than tab.

​ CanBackquote函数报告字符串s是否可以表示为单行反引号字符串而不带控制字符(除制表符之外)。

CanBackquote函数会返回一个布尔值，指示是否可以使用Go语言中的反引号来包裹给定的字符串。如果可以使用反引号，则返回true，否则返回false。

CanBackquote Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	fmt.Println(strconv.CanBackquote("Fran & Freddie's Diner ☺"))
	fmt.Println(strconv.CanBackquote("`can't backquote this`"))

}
Output:

true
false

func FormatBool

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func FormatBool(b bool) string

FormatBool returns “true” or “false” according to the value of b.

​ FormatBool函数根据 b 的值返回 “true” 或 “false”。

FormatBool Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	v := true
	s := strconv.FormatBool(v)
	fmt.Printf("%T, %v\n", s, s)

}
Output:

string, true

func FormatComplex <- go1.15

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func FormatComplex(c complex128, fmt byte, prec, bitSize int) string

FormatComplex converts the complex number c to a string of the form (a+bi) where a and b are the real and imaginary parts, formatted according to the format fmt and precision prec.

​ FormatComplex函数将复数 c 格式化为 (a+bi) 形式的字符串，其中 a 和 b 是实部和虚部，根据格式fmt和精度prec进行格式化。

The format fmt and precision prec have the same meaning as in FormatFloat. It rounds the result assuming that the original was obtained from a complex value of bitSize bits, which must be 64 for complex64 and 128 for complex128.

​ 格式 fmt 和精度 prec 的含义与 FormatFloat函数 相同。它假定原始值是从 bitSize 位的复数值(complex64 的 bitSize 必须是 64，而 complex128 的 bitSize 必须是 128)获得的，四舍五入结果。

func FormatFloat

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func FormatFloat(f float64, fmt byte, prec, bitSize int) string

FormatFloat converts the floating-point number f to a string, according to the format fmt and precision prec. It rounds the result assuming that the original was obtained from a floating-point value of bitSize bits (32 for float32, 64 for float64).

​ FormatFloat函数将浮点数 f 格式化为字符串，格式由 fmt 和精度 prec 指定。它假定原始值是从 bitSize 位(float32 为 32，float64 为 64)的浮点数值获得的。

The format fmt is one of ‘b’ (-ddddp±ddd, a binary exponent), ’e’ (-d.dddde±dd, a decimal exponent), ‘E’ (-d.ddddE±dd, a decimal exponent), ‘f’ (-ddd.dddd, no exponent), ‘g’ (’e’ for large exponents, ‘f’ otherwise), ‘G’ (‘E’ for large exponents, ‘f’ otherwise), ‘x’ (-0xd.ddddp±ddd, a hexadecimal fraction and binary exponent), or ‘X’ (-0Xd.ddddP±ddd, a hexadecimal fraction and binary exponent).

​ 格式 fmt 是 ‘b’(-ddddp±ddd，二进制指数)、’e’(-d.dddde±dd，十进制指数)、‘E’(-d.ddddE±dd，十进制指数)、‘f’(-ddd.dddd，无指数)、‘g’(大指数时为 ’e’，否则为 ‘f’)、‘G’(大指数时为 ‘E’，否则为 ‘f’)、‘x’(-0xd.ddddp±ddd，十六进制小数和二进制指数)或 ‘X’(-0Xd.ddddP±ddd，十六进制小数和二进制指数)之一。

The precision prec controls the number of digits (excluding the exponent) printed by the ’e’, ‘E’, ‘f’, ‘g’, ‘G’, ‘x’, and ‘X’ formats. For ’e’, ‘E’, ‘f’, ‘x’, and ‘X’, it is the number of digits after the decimal point. For ‘g’ and ‘G’ it is the maximum number of significant digits (trailing zeros are removed). The special precision -1 uses the smallest number of digits necessary such that ParseFloat will return f exactly.

​ 精度 prec 控制由 ’e’、‘E’、‘f’、‘g’、‘G’、‘x’ 和 ‘X’ 格式打印的数字的位数(不包括指数)。对于 ’e’、‘E’、‘f’、‘x’ 和 ‘X’，它是小数点后的数字位数。对于 ‘g’ 和 ‘G’，它是最大的有效数字位数(尾随零被删除)。特殊精度 -1 使用最少数量的位数，使 ParseFloat 精确返回 f。

FormatFloat Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	v := 3.1415926535

	s32 := strconv.FormatFloat(v, 'E', -1, 32)
	fmt.Printf("%T, %v\n", s32, s32)

	s64 := strconv.FormatFloat(v, 'E', -1, 64)
	fmt.Printf("%T, %v\n", s64, s64)

}
Output:

string, 3.1415927E+00
string, 3.1415926535E+00

func FormatInt

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func FormatInt(i int64, base int) string

FormatInt returns the string representation of i in the given base, for 2 <= base <= 36. The result uses the lower-case letters ‘a’ to ‘z’ for digit values >= 10.

​ FormatInt函数返回基于给定进制 base 中 i 的字符串表示形式，2 <= base <= 36。结果对于值 >= 10 的数字使用小写字母 ‘a’ 到 ‘z’。

FormatInt Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	v := int64(-42)

	s10 := strconv.FormatInt(v, 10)
	fmt.Printf("%T, %v\n", s10, s10)

	s16 := strconv.FormatInt(v, 16)
	fmt.Printf("%T, %v\n", s16, s16)

}
Output:

string, -42
string, -2a

func FormatUint

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func FormatUint(i uint64, base int) string

FormatUint returns the string representation of i in the given base, for 2 <= base <= 36. The result uses the lower-case letters ‘a’ to ‘z’ for digit values >= 10.

​ FormatUint函数返回基于给定进制 base 中 i 的字符串表示形式，2 <= base <= 36。结果对于值 >= 10 的数字使用小写字母 ‘a’ 到 ‘z’。

FormatUint Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	v := uint64(42)

	s10 := strconv.FormatUint(v, 10)
	fmt.Printf("%T, %v\n", s10, s10)

	s16 := strconv.FormatUint(v, 16)
	fmt.Printf("%T, %v\n", s16, s16)

}
Output:

string, 42
string, 2a

func IsGraphic <- go1.6

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func IsGraphic(r rune) bool

IsGraphic reports whether the rune is defined as a Graphic by Unicode. Such characters include letters, marks, numbers, punctuation, symbols, and spaces, from categories L, M, N, P, S, and Zs.

​ IsGraphic函数报告 r 是否被 Unicode 定义为图形字符。这些字符包括类别 L、M、N、P、S和Z。

IsGraphic Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	shamrock := strconv.IsGraphic('☘')
	fmt.Println(shamrock)

	a := strconv.IsGraphic('a')
	fmt.Println(a)

	bel := strconv.IsGraphic('\007')
	fmt.Println(bel)

}
Output:

true
true
false

func IsPrint

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func IsPrint(r rune) bool

IsPrint reports whether the rune is defined as printable by Go, with the same definition as unicode.IsPrint: letters, numbers, punctuation, symbols and ASCII space.

​ IsPrint 函数判断 rune 是否可打印，其定义与 unicode.IsPrint 相同：字母、数字、标点符号、符号和 ASCII 空格都是可打印的。

IsPrint Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	c := strconv.IsPrint('\u263a')
	fmt.Println(c)

	bel := strconv.IsPrint('\007')
	fmt.Println(bel)

}
Output:

true
false

func Itoa

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func Itoa(i int) string

Itoa is equivalent to FormatInt(int64(i), 10).

​ Itoa函数将 int 类型的 i 转换成对应的十进制字符串。

​ Itoa函数等同于FormatInt(int64(i), 10)。

Itoa Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	i := 10
	s := strconv.Itoa(i)
	fmt.Printf("%T, %v\n", s, s)

}
Output:

string, 10

func ParseBool

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func ParseBool(str string) (bool, error)

ParseBool returns the boolean value represented by the string. It accepts 1, t, T, TRUE, true, True, 0, f, F, FALSE, false, False. Any other value returns an error.

​ ParseBool 函数将字符串 str 解析为 bool 类型的值。它接受 1、t、T、TRUE、true、True、0、f、F、FALSE、false、False，其他任何值都会返回一个错误。

ParseBool Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	v := "true"
	if s, err := strconv.ParseBool(v); err == nil {
		fmt.Printf("%T, %v\n", s, s)
	}

}
Output:

bool, true

func ParseComplex <- go1.15

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func ParseComplex(s string, bitSize int) (complex128, error)

ParseComplex converts the string s to a complex number with the precision specified by bitSize: 64 for complex64, or 128 for complex128. When bitSize=64, the result still has type complex128, but it will be convertible to complex64 without changing its value.

​ ParseComplex函数将字符串s转换为复数，精度由bitSize指定：64表示complex64，128表示complex128。当bitSize=64时，结果仍为complex128类型，但可以转换为complex64而不改变其值。

The number represented by s must be of the form N, Ni, or N±Ni, where N stands for a floating-point number as recognized by ParseFloat, and i is the imaginary component. If the second N is unsigned, a + sign is required between the two components as indicated by the ±. If the second N is NaN, only a + sign is accepted. The form may be parenthesized and cannot contain any spaces. The resulting complex number consists of the two components converted by ParseFloat.

​ s表示为N、Ni或N±Ni的形式，其中N表示由ParseFloat函数识别的浮点数，i是虚部。如果第二个N是无符号的，则需要+符号将两个组件连接起来，如±所示。如果第二个N是NaN，则只接受+符号。该形式可以括在括号中，不能包含任何空格。由ParseFloat函数转换的两个组件构成的结果复数。

The errors that ParseComplex returns have concrete type *NumError and include err.Num = s.

​ ParseComplex函数返回的错误具有具体类型*NumError，并包括err.Num = s。

If s is not syntactically well-formed, ParseComplex returns err.Err = ErrSyntax.

​ 如果s的语法不正确，则ParseComplex函数返回err.Err = ErrSyntax。

If s is syntactically well-formed but either component is more than 1/2 ULP away from the largest floating point number of the given component’s size, ParseComplex returns err.Err = ErrRange and c = ±Inf for the respective component.

​ 如果s的语法正确，但任一组件距离给定组件大小的最大浮点数超过1/2 ULP，则ParseComplex函数返回err.Err = ErrRange和c =±Inf，分别对应于组件。

func ParseFloat

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func ParseFloat(s string, bitSize int) (float64, error)

ParseFloat converts the string s to a floating-point number with the precision specified by bitSize: 32 for float32, or 64 for float64. When bitSize=32, the result still has type float64, but it will be convertible to float32 without changing its value.

​ ParseFloat函数将字符串s转换为浮点数，精度由bitSize指定：32表示float32，64表示float64。当bitSize=32时，结果仍为float64类型，但可以转换为float32而不改变其值。

ParseFloat accepts decimal and hexadecimal floating-point numbers as defined by the Go syntax for floating-point literals. If s is well-formed and near a valid floating-point number, ParseFloat returns the nearest floating-point number rounded using IEEE754 unbiased rounding. (Parsing a hexadecimal floating-point value only rounds when there are more bits in the hexadecimal representation than will fit in the mantissa.)

​ ParseFloat函数接受十进制和十六进制的浮点数，这是Go语法对浮点数字面的定义。如果s是格式良好且接近有效的浮点数，ParseFloat函数会返回最近的浮点数，并使用IEEE754无偏差四舍五入。(解析十六进制浮点数时，只有当十六进制表示的位数多于尾数时才会进行四舍五入)。

The errors that ParseFloat returns have concrete type *NumError and include err.Num = s.

​ ParseFloat函数返回的错误具有具体类型*NumError，并包括err.Num = s。

If s is not syntactically well-formed, ParseFloat returns err.Err = ErrSyntax.

​ 如果s的语法不正确，则ParseFloat函数返回err.Err = ErrSyntax。

If s is syntactically well-formed but is more than 1/2 ULP away from the largest floating point number of the given size, ParseFloat returns f = ±Inf, err.Err = ErrRange.

​ 如果s的语法正确，但距离给定大小的最大浮点数超过1/2 ULP，则ParseFloat函数返回f =±Inf，err.Err = ErrRange。

ParseFloat recognizes the string “NaN”, and the (possibly signed) strings “Inf” and “Infinity” as their respective special floating point values. It ignores case when matching.

​ ParseFloat函数将字符串"NaN"和(可能带符号的)字符串"Inf"和"Infinity"识别为它们各自的特殊浮点值。它在匹配时忽略大小写。

ParseFloat Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	v32 := "-354634382"
	if s, err := strconv.ParseInt(v32, 10, 32); err == nil {
		fmt.Printf("%T, %v\n", s, s)
	}
	if s, err := strconv.ParseInt(v32, 16, 32); err == nil {
		fmt.Printf("%T, %v\n", s, s)
	}

	v64 := "-3546343826724305832"
	if s, err := strconv.ParseInt(v64, 10, 64); err == nil {
		fmt.Printf("%T, %v\n", s, s)
	}
	if s, err := strconv.ParseInt(v64, 16, 64); err == nil {
		fmt.Printf("%T, %v\n", s, s)
	}

}

func ParseInt

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func ParseInt(s string, base int, bitSize int) (i int64, err error)

ParseInt interprets a string s in the given base (0, 2 to 36) and bit size (0 to 64) and returns the corresponding value i.

​ ParseInt函数将给定进制(0、2到36)和位大小(0到64)的字符串s解释为对应的值i并返回。

The string may begin with a leading sign: “+” or “-”.

​ 字符串可能以符号"+“或”-“开头。

If the base argument is 0, the true base is implied by the string’s prefix following the sign (if present): 2 for “0b”, 8 for “0” or “0o”, 16 for “0x”, and 10 otherwise. Also, for argument base 0 only, underscore characters are permitted as defined by the Go syntax for integer literals.

​ 如果base参数为0，则真实基数是由字符串前缀随后的符号(如果存在)隐含指定的：对于"0b”，基数为2；对于"0"或"0o"，基数为8；对于"0x"，基数为16；否则基数为10。此外，仅针对base为0的情况，根据Go整数字面量的语法，下划线字符是允许的。

The bitSize argument specifies the integer type that the result must fit into. Bit sizes 0, 8, 16, 32, and 64 correspond to int, int8, int16, int32, and int64. If bitSize is below 0 or above 64, an error is returned.

​ bitSize参数指定结果必须适合的整数类型。位大小0、8、16、32和64对应于int、int8、int16、int32和int64。如果bitSize小于0或大于64，则会返回错误。

The errors that ParseInt returns have concrete type *NumError and include err.Num = s. If s is empty or contains invalid digits, err.Err = ErrSyntax and the returned value is 0; if the value corresponding to s cannot be represented by a signed integer of the given size, err.Err = ErrRange and the returned value is the maximum magnitude integer of the appropriate bitSize and sign.

​ ParseInt函数返回的错误具有具体类型*NumError，并包括err.Num = s。如果s为空或包含无效数字，则err.Err = ErrSyntax，返回值为0；如果s对应的值无法由给定大小的有符号整数表示，则err.Err = ErrRange，返回值为适当的bitSize和符号的最大幅度整数。

ParseInt Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	v := "42"
	if s, err := strconv.ParseUint(v, 10, 32); err == nil {
		fmt.Printf("%T, %v\n", s, s)
	}
	if s, err := strconv.ParseUint(v, 10, 64); err == nil {
		fmt.Printf("%T, %v\n", s, s)
	}

}
Output:

uint64, 42
uint64, 42

func ParseUint

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func ParseUint(s string, base int, bitSize int) (uint64, error)

ParseUint is like ParseInt but for unsigned numbers.

​ ParseUint函数类似于ParseInt函数，但用于无符号数字。

A sign prefix is not permitted.

​ 不允许符号前缀。

ParseUint Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	// This string literal contains a tab character.
	s := strconv.Quote(`"Fran & Freddie's Diner	☺"`)
	fmt.Println(s)

}
Output:

"\"Fran & Freddie's Diner\t☺\""

func Quote

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func Quote(s string) string

Quote returns a double-quoted Go string literal representing s. The returned string uses Go escape sequences (\t, \n, \xFF, \u0100) for control characters and non-printable characters as defined by IsPrint.

​ Quote函数返回表示字符串s的双引号Go字符串文本。返回的字符串使用Go转义序列(\t，\n，\xFF，\u0100)表示控制字符和非可打印字符，如IsPrint定义的。

Quote Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	// This string literal contains a tab character.
	s := strconv.Quote(`"Fran & Freddie's Diner	☺"`)
	fmt.Println(s)

}
Output:

"\"Fran & Freddie's Diner\t☺\""

func QuoteRune

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func QuoteRune(r rune) string

QuoteRune returns a single-quoted Go character literal representing the rune. The returned string uses Go escape sequences (\t, \n, \xFF, \u0100) for control characters and non-printable characters as defined by IsPrint. If r is not a valid Unicode code point, it is interpreted as the Unicode replacement character U+FFFD.

​ QuoteRune函数返回表示符文的单引号Go字符文本。返回的字符串使用Go转义序列(\t，\n，\xFF，\u0100)表示控制字符和非可打印字符，如IsPrint函数定义的。如果r不是有效的Unicode代码点，则将其解释为Unicode替换字符U+FFFD。

\u和\U转义字符表示Unicode编码时，后面必须跟着4个(\u)或8个(\U)十六进制数字来表示该字符的Unicode编码，例如\u4E2D表示中文字符"中"的Unicode编码，\U0001F600表示笑脸表情的Unicode编码。需要注意的是，\u只能用来表示码位在BMP(基本多文种平面，即Unicode的第0平面)中的字符，而\U可以用来表示码位在任意平面的字符。

​ U+数字表示Unicode编码时，U后面紧跟着的数字表示该字符的Unicode编码值，例如U+4E2D表示中文字符"中"的Unicode编码，U+1F600表示笑脸表情的Unicode编码。需要注意的是，U+数字只能用来表示码位在BMP中的字符，而不能表示码位在其他平面中的字符，需要使用\U或者专门的非BMP编码方式来表示。

​ 总之，\u和\U是表示Unicode编码的通用转义字符，适用于任何字符，而U+数字只适用于码位在BMP中的字符。

BMP(Basic Multilingual Plane，基本多文种平面)是 Unicode 标准中的一个字符编码平面，其中包含了 0x0000 至 0xFFFF 这 65536 个字符的编码。这个编码范围内包含了大部分常用的字符，如 ASCII 码中的字符、拉丁字母、希腊字母、西里尔字母、汉字等等。因此，BMP 平面也被称为 Unicode 字符集的核心区域。

在 Go 语言中，使用 \u+四位十六进制数来表示 BMP 平面中的 Unicode 字符。例如，\u4e2d表示汉字"中"的 Unicode 编码 U+4E2D。而使用 \U+八位十六进制数来表示 Unicode 字符，这种表示方式可以用来表示 BMP 平面以外的字符，例如 \U0001F600 表示一个笑脸表情"😀"，它的 Unicode 编码为 U+1F600，超出了 BMP 平面的编码范围。

QuoteRune Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	s := strconv.QuoteRune('☺')
	fmt.Println(s)

}
Output:

'☺'

func QuoteRuneToASCII

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func QuoteRuneToASCII(r rune) string

QuoteRuneToASCII returns a single-quoted Go character literal representing the rune. The returned string uses Go escape sequences (\t, \n, \xFF, \u0100) for non-ASCII characters and non-printable characters as defined by IsPrint. If r is not a valid Unicode code point, it is interpreted as the Unicode replacement character U+FFFD.

​ QuoteRuneToASCII函数返回表示符文的 Go 单引号字符字面量。返回的字符串使用 Go 转义序列 (\t, \n, \xFF, \u0100) 表示非 ASCII 字符和由 IsPrint 定义的不可打印字符。如果 r 不是一个有效的 Unicode 代码点，则将其解释为 Unicode 替换字符 U+FFFD。

QuoteRuneToASCII Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	s := strconv.QuoteRuneToASCII('☺')
	fmt.Println(s)

}
Output:

'\u263a'

func QuoteRuneToGraphic <- go1.6

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func QuoteRuneToGraphic(r rune) string

QuoteRuneToGraphic returns a single-quoted Go character literal representing the rune. If the rune is not a Unicode graphic character, as defined by IsGraphic, the returned string will use a Go escape sequence (\t, \n, \xFF, \u0100). If r is not a valid Unicode code point, it is interpreted as the Unicode replacement character U+FFFD.

​ QuoteRuneToGraphic函数返回表示符文的 Go 单引号字符字面量。如果符文不是一个 Unicode 图形字符，如由 IsGraphic函数定义，返回的字符串将使用 Go 转义序列 (\t, \n, \xFF, \u0100)。如果 r 不是一个有效的 Unicode 代码点，则将其解释为 Unicode 替换字符 U+FFFD。

QuoteRuneToGraphic Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	s := strconv.QuoteRuneToGraphic('☺')
	fmt.Println(s)

	s = strconv.QuoteRuneToGraphic('\u263a')
	fmt.Println(s)

	s = strconv.QuoteRuneToGraphic('\u000a')
	fmt.Println(s)

	s = strconv.QuoteRuneToGraphic('	') // tab character
	fmt.Println(s)

}
Output:

'☺'
'☺'
'\n'
'\t'

func QuoteToASCII

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func QuoteToASCII(s string) string

QuoteToASCII returns a double-quoted Go string literal representing s. The returned string uses Go escape sequences (\t, \n, \xFF, \u0100) for non-ASCII characters and non-printable characters as defined by IsPrint.

​ QuoteToASCII函数返回表示字符串 s 的 Go 双引号字符串字面量。返回的字符串使用 Go 转义序列 (\t, \n, \xFF, \u0100) 表示非 ASCII 字符和由 IsPrint函数定义的不可打印字符。

QuoteToASCII Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	// 这个字符串字面量包含一个制表符。
	s := strconv.QuoteToASCII(`"Fran & Freddie's Diner	☺"`)
	fmt.Println(s)

}
Output:

"\"Fran & Freddie's Diner\t\u263a\""

func QuoteToGraphic <- go1.6

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func QuoteToGraphic(s string) string

QuoteToGraphic returns a double-quoted Go string literal representing s. The returned string leaves Unicode graphic characters, as defined by IsGraphic, unchanged and uses Go escape sequences (\t, \n, \xFF, \u0100) for non-graphic characters.

​ QuoteToGraphic函数返回表示字符串 s 的 Go 双引号字符串字面量。返回的字符串保留 Unicode 图形字符(由 IsGraphic函数定义)，对于非图形字符使用 Go 转义序列 (\t, \n, \xFF, \u0100)。

QuoteToGraphic Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	s := strconv.QuoteToGraphic("☺")
	fmt.Println(s)

	// This string literal contains a tab character.
	s = strconv.QuoteToGraphic("This is a \u263a	\u000a")
	fmt.Println(s)

	s = strconv.QuoteToGraphic(`" This is a ☺ \n "`)
	fmt.Println(s)

}
Output:

"☺"
"This is a ☺\t\n"
"\" This is a ☺ \\n \""

func QuotedPrefix <- go1.17

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func QuotedPrefix(s string) (string, error)

QuotedPrefix returns the quoted string (as understood by Unquote) at the prefix of s. If s does not start with a valid quoted string, QuotedPrefix returns an error.

​ QuotedPrefix函数返回 s 的前缀处的带引号字符串(如 Unquote函数理解的那样)。如果 s 不以有效的带引号字符串开头，则 QuotedPrefix函数返回一个错误。

func Unquote

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func Unquote(s string) (string, error)

Unquote interprets s as a single-quoted, double-quoted, or backquoted Go string literal, returning the string value that s quotes. (If s is single-quoted, it would be a Go character literal; Unquote returns the corresponding one-character string.)

​ Unquote函数将 s 解释为单引号、双引号或反引号包裹的 Go 字符串字面量，并返回 s 引用的字符串值。(如果 s 是单引号引用的，则它是一个 Go 字符字面量；Unquote函数返回相应的单个字符字符串。)

​ Unquote 函数接收一个字符串参数 s，并返回一个解析后的字符串值和一个错误。如果解析成功，则该错误为 nil；否则，错误包含一个具体的错误消息。

​ Unquote 函数支持三种引号类型：单引号、双引号和反引号。其中，单引号表示 Go 语言字符字面值，双引号表示 Go 语言字符串字面值，反引号表示 Go 语言原始字符串字面值。

​ 在解析字符串字面值时，Unquote 函数会自动处理转义字符，例如 \t、\n、" 和 ’ 等。同时，它还支持 Unicode 转义，例如 \uXXXX 和 \UXXXXXXXX。

Unquote Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
    s, err := strconv.Unquote(`"You can unquote a string with quotes"`)
	fmt.Printf("%q, %v\n", s, err)
	s, err := strconv.Unquote("You can't unquote a string without quotes")
	fmt.Printf("%q, %v\n", s, err)
	s, err = strconv.Unquote("\"The string must be either double-quoted\"")
	fmt.Printf("%q, %v\n", s, err)
	s, err = strconv.Unquote("`or backquoted.`")
	fmt.Printf("%q, %v\n", s, err)
	s, err = strconv.Unquote("'\u263a'") // single character only allowed in single quotes
	fmt.Printf("%q, %v\n", s, err)
	s, err = strconv.Unquote("'\u2639\u2639'")
	fmt.Printf("%q, %v\n", s, err)

}
Output:
"You can unquote a string with quotes",<nil>
"", invalid syntax
"The string must be either double-quoted", <nil>
"or backquoted.", <nil>
"☺", <nil>
"", invalid syntax

func UnquoteChar

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func UnquoteChar(s string, quote byte) (value rune, multibyte bool, tail string, err error)

UnquoteChar decodes the first character or byte in the escaped string or character literal represented by the string s. It returns four values:

​ UnquoteChar函数解码字符串 s 中转义的字符串或字符字面值表示的第一个字符或字节。它返回四个值：

  1. value, the decoded Unicode code point or byte value;
  2. value，解码后的 Unicode 码点或字节值；
  3. multibyte, a boolean indicating whether the decoded character requires a multibyte UTF-8 representation;
  4. multibyte，一个布尔值，指示解码后的字符是否需要多字节 UTF-8 表示形式；
  5. tail, the remainder of the string after the character; and
  6. tail，字符之后剩余的字符串；
  7. an error that will be nil if the character is syntactically valid.
  8. 一个错误，如果字符在语法上有效，则为 nil。

The second argument, quote, specifies the type of literal being parsed and therefore which escaped quote character is permitted. If set to a single quote, it permits the sequence ' and disallows unescaped ‘. If set to a double quote, it permits " and disallows unescaped “. If set to zero, it does not permit either escape and allows both quote characters to appear unescaped.

​ 第二个参数 quote 指定要解析的文本类型，因此允许哪个转义引号字符。如果设置为单引号，则允许序列 '，并禁止未转义的'。如果设置为双引号，则允许 " 并禁止未转义的"。如果设置为零值，则不允许任何转义，且允许两个引号字符未转义出现。

UnquoteChar Example

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package main

import (
	"fmt"
	"log"
	"strconv"
)

func main() {
	v, mb, t, err := strconv.UnquoteChar(`\"Fran & Freddie's Diner\"`, '"')
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println("value:", string(v))
	fmt.Println("multibyte:", mb)
	fmt.Println("tail:", t)
    // 解码转义字符
    s := `\"hello\"`
    value, multibyte, tail, err := strconv.UnquoteChar(s, '"')
    if err != nil {
        fmt.Println(err)
    }
    fmt.Println(value, multibyte, tail)
	// 解码Unicode字符
	s = `\u0048\u0065\u006c\u006c\u006f\u0020\u0057\u006f\u0072\u006c\u0064`
    value, multibyte, tail, err = strconv.UnquoteChar(s, '\'')
    if err != nil {
        fmt.Println(err)
    }
    fmt.Printf("%c %t %s", value, multibyte, tail)

}
Output:

value: "
multibyte: false
tail: Fran & Freddie's Diner\"
34 false hello\"
H true \u0065\u006c\u006c\u006f\u0020\u0057\u006f\u0072\u006c\u0064

类型

type NumError

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type NumError struct {
	Func string // 失败的函数(ParseBool, ParseInt, ParseUint, ParseFloat, ParseComplex) the failing function (ParseBool, ParseInt, ParseUint, ParseFloat, ParseComplex)
	Num  string // 输入的数据 the input
	Err  error  // 转换失败的原因(例如 ErrRange, ErrSyntax, 等)。 the reason the conversion failed (e.g. ErrRange, ErrSyntax, etc.)
}

A NumError records a failed conversion.

​ NumError函数记录了转换失败的情况。

Example

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package main

import (
	"fmt"
	"strconv"
)

func main() {
	str := "Not a number"
	if _, err := strconv.ParseFloat(str, 64); err != nil {
		e := err.(*strconv.NumError)
		fmt.Println("Func:", e.Func)
		fmt.Println("Num:", e.Num)
		fmt.Println("Err:", e.Err)
		fmt.Println(err)
	}

}
Output:

Func: ParseFloat
Num: Not a number
Err: invalid syntax
strconv.ParseFloat: parsing "Not a number": invalid syntax

(*NumError) Error

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func (e *NumError) Error() string

(*NumError) Unwrap <- go1.14

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func (e *NumError) Unwrap() error
最后修改 September 6, 2024: 完成将标准库的版本更新为go1.23.0 (23dc927)