.NET中的base_convert

Question

.NET是否具有与PHP的base_convert等效的本机函数,还是需要编写自己的函数？我想从任何基数转换为任何其他基数 - 其中'to'基数或'from'基数可以是任何整数2-36.

PHP函数示例:base_convert($ number_to_convert,$ from_base,$ to_base)

// convert 101 from binary to decimal
echo base_convert('101', 2, 10);
// 5

正如Luke在Jon Skeet的回答中所指出的那样:Convert.ToString无法处理任何基数的转换,只有2,8,10和16

更新:显然,答案是:不,没有本地方式.下面,Erik展示了一种方法.另一个实现是:http://www.codeproject.com/KB/macros/Convert.aspx

Answer 1

编辑:这个答案非常方便,但只适用于基地2,8,10和16

你可以使用Convert.ToInt32(text, base)然后Convert.ToString(number, base):

using System;

class Test
{
    static void Main()
    {
        int number = Convert.ToInt32("101", 2);
        string text = Convert.ToString(number, 10);
        Console.WriteLine(text); // Prints 5
    }
}

如果您要转换到基数10或从基数10转换,则无需指定 - 这是默认值.

请注意,这仅适用于基数2,8,10和16.如果您还需要其他任何内容,则必须编写自己的解析器/格式化程序.

Answer 2

这里有一些代码可以将整数转换为最多36的任意基数,并将基础x值的字符串表示转换为整数(给定基数):

class Program {
    static void Main(string[] args) {
        int b10 = 123;
        int targetBase = 5;

        string converted = ConvertToBase(b10, targetBase);
        int convertedBack = ConvertFromBase(converted, targetBase);

        string base3 = "212210";
        string base7 = ConvertFromBaseToBase(base3, 3, 7);

        Console.WriteLine(converted);
        Console.WriteLine(convertedBack);
        Console.WriteLine(base7);
        Console.ReadLine();
    }

    private const string chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    private static string ConvertToBase(int b10, int targetBase) {
        if (targetBase < 2) throw new ArgumentException("Target base must be greater than 2.", "targetBase");
        if (targetBase > 36) throw new ArgumentException("Target base must be less than 36.", "targetBase");

        if (targetBase == 10) return b10.ToString();

        StringBuilder result = new StringBuilder();

        while (b10 >= targetBase) {
            int mod = b10 % targetBase;
            result.Append(chars[mod]);
            b10 = b10 / targetBase;
        }

        result.Append(chars[b10]);

        return Reverse(result.ToString());
    }

    private static int ConvertFromBase(string bx, int fromBase) {
        if (fromBase < 2) throw new ArgumentException("Base must be greater than 2.", "fromBase");
        if (fromBase > 36) throw new ArgumentException("Base must be less than 36.", "fromBase");

        if (fromBase == 10) return int.Parse(bx);

        bx = Reverse(bx);
        int acc = 0;

        for (int i = 0; i < bx.Length; i++) {
            int charValue = chars.IndexOf(bx[i]);
            acc += (int)Math.Pow(fromBase, i) * charValue;
        }

        return acc;
    }

    public static string ConvertFromBaseToBase(string bx, int fromBase, int toBase) {
        int b10 = ConvertFromBase(bx, fromBase);
        return ConvertToBase(b10, toBase);
    }

    public static string Reverse(string s) {
        char[] charArray = new char[s.Length];
        int len = s.Length - 1;
        for (int i = 0; i <= len; i++)
            charArray[i] = s[len - i];
        return new string(charArray);
    }
}

如果你不关心显示这些值,你可以在你的字符集中使用扩展字符 - 如果你坚持使用简单的ascii,理论上你可以有base256值.除此之外,我建议不要使用字符,而是使用其他一些可识别的唯一值 - 尽管我没有太多看到它的价值.