判断两个字符相似度

#region 判断两个字符相似度
        //公式：l = q/(q+r+s);
        private string Similarity(string a, string b)
        {

string a1 = "";
            string b1 = "";

//消除重复
            for(int i=0;i<a.Length;i++)  
            {  
             string emtpy=a.Substring(i,1).ToString();  
             if(a1.Length==0)  
             {  
              a1=emtpy;  
             }  
             if(a1.IndexOf(emtpy,0)<0)  
             {  
              a1+=emtpy;  
             }  
            }
            //消除重复
            for (int i = 0; i < b.Length; i++)
            {
                string emtpy = b.Substring(i, 1).ToString();
                if (b1.Length == 0)
                {
                    b1 = emtpy;
                }
                if (b1.IndexOf(emtpy, 0) < 0)
                {
                    b1 += emtpy;
                }
            }

//计算相似度
            if (a1.Length >= b1.Length)
            {
                int q = 0;
                for (int i = 0; i < b1.Length; i++)
                {
                    for (int j = 0; j < a1.Length; j++)
                    {
                        if (b1.Substring(i, 1).ToString() == a1.Substring(j, 1).ToString())
                        {
                            q += 1;
                        }

}
                }
                System.Globalization.NumberFormatInfo provider = new System.Globalization.NumberFormatInfo();
                provider.PercentDecimalDigits = 2;//小数点保留几位数.
                provider.PercentPositivePattern = 1;//百分号出现在何处.
                double result = (double)q / (a1.Length + b1.Length - q);//一定要用double类型.
                return result.ToString("P", provider);
            }
            else
            {
                int q = 0;
                for (int i = 0; i < a1.Length; i++)
                {
                    for (int j = 0; j < b1.Length; j++)
                    {
                        if (a1.Substring(i, 1).ToString() == b1.Substring(j, 1).ToString())
                        {
                            q += 1;
                        }

}
                }
                System.Globalization.NumberFormatInfo provider = new System.Globalization.NumberFormatInfo();
                provider.PercentDecimalDigits = 2;//小数点保留几位数.
                provider.PercentPositivePattern = 1;//百分号出现在何处.
                double result = (double)q / (a1.Length + b1.Length - q);//一定要用double类型.
                return result.ToString("P", provider);

}

       
    }
 #endregion

装载http://blog.sina.com.cn/s/blog_5f254b8a0100t4hy.html

参考文章：http://www.360doc.com/content/09/0201/10/96202_2430832.shtml