StringToNumber.md

字符串与数值间的转换

• int to string

    s := strconv.Itoa(i)
    //等价于
    s := strconv.FormatInt(int64(i), 10)
  

• int64 to string

    i := int64(123)
    s := strconv.FormatInt(i, 10)
    //对于无符号整形，可以使用
    FormatUint(i uint64, base int)
  

• string to int

    i, err := strconv.Atoi(s)
  

• string to int64

    i, err := strconv.ParseInt(s, 10, 64)
    // 第二个参数可以为16，即s为16进制字符串
  

• hex to int64

    strconv.ParseInt("C40C5253", 16, 64)
  

• float转string

    s := "3.1415926535"
    v1, err := strconv.ParseFloat(v, 32)
    v2, err := strconv.ParseFloat(v, 64)
  
    v := 3.1415926535
    s1 := strconv.FormatFloat(v, 'E', -1, 32)//float32
    s2 := strconv.FormatFloat(v, 'E', -1, 64)//float64
    // 第二个参数,fmt解释
    // '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，没有指数)
    // 'g' ('e':大指数，'f':其它情况)
    // 'G' ('E':大指数，'f':其它情况)
    // 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), or
    // 'G' ('E' for large exponents, 'f' otherwise).
    //
    // The precision prec controls the number of digits
    // (excluding the exponent) printed by the 'e', 'E', 'f', 'g', and 'G' formats.
    // For 'e', 'E', and 'f' it is the number of digits after the decimal point.
    // For 'g' and 'G' it is the total number of digits.
    // The special precision -1 uses the smallest number of digits
    // necessary such that ParseFloat will return f exactly.