七、C#正则表达式匹配字符串

正则表达式可以快速判断所给字符串是否某种指定格式。这里将一些常用的方法封装进一个字符串工具类中。

  1 public static class StringTool
  2 {
  3     /// <summary>
  4     /// 判断字符串是否纯数字
  5     /// </summary>
  6     /// <param name="str"></param>
  7     /// <returns></returns>
  8     public static bool IsNumber(string str)
  9     {
 10         return Regex.IsMatch(str, @"^[0-9]+$");
 11     }
 12 
 13     /// <summary>
 14     /// 判断字符串是否纯字母
 15     /// </summary>
 16     /// <param name="str"></param>
 17     /// <returns></returns>
 18     public static bool IsLetter(string str)
 19     {
 20         return Regex.IsMatch(str, @"^[A-Za-z]+$");
 21     }
 22 
 23     /// <summary>
 24     /// 判断字符串是否字母或数字的组合
 25     /// </summary>
 26     /// <param name="str"></param>
 27     /// <returns></returns>
 28     public static bool IsLetterOrNumber(string str)
 29     {
 30         return Regex.IsMatch(str, @"(?i)^[0-9a-z]+$");
 31     }
 32 
 33     /// <summary>
 34     /// 统计字符串中汉字个数   
 35     /// </summary>
 36     /// <param name="str"></param>
 37     /// <returns></returns>
 38     public static int CountChinese(string str)
 39     {
 40         return str.Count(c => Regex.IsMatch(c.ToString(), @"^[\u4E00-\u9FA5]{0,}$"));
 41     }
 42 
 43     /// <summary>
 44     /// 判断字符串是否纯中文
 45     /// </summary>
 46     /// <param name="str"></param>
 47     /// <returns></returns>
 48     public static bool IsChinese(string str)
 49     {
 50         return Regex.IsMatch(str, @"^[\u4e00-\u9fa5],{0,}$");
 51     }
 52 
 53     /// <summary>
 54     /// 判断字符串中是否包含中文
 55     /// </summary>
 56     /// <param name="str"></param>
 57     /// <returns></returns>
 58     public static bool HasChinese(string str)
 59     {
 60         return Regex.IsMatch(str, @"[\u4e00-\u9fa5]");
 61     }
 62 
 63     /// <summary>
 64     /// 统计字符串中全角字符个数
 65     /// </summary>
 66     /// <param name="str"></param>
 67     /// <returns></returns>
 68     public static int CountSbcCase(string str)
 69     {
 70         return Encoding.Default.GetByteCount(str) - str.Length;
 71     }
 72 
 73     /// <summary>
 74     /// 判断字符串中是否包含全角字符
 75     /// </summary>
 76     /// <param name="str"></param>
 77     /// <returns></returns>
 78     public static bool HasSbcCase(string str)
 79     {
 80         return CountSbcCase(str) > 0;
 81     }
 82 
 83     /// <summary>
 84     /// 统计字符串中半角字符个数
 85     /// </summary>
 86     /// <param name="str"></param>
 87     /// <returns></returns>
 88     public static int CountDbcCase(string str)
 89     {
 90         return str.Length - CountSbcCase(str);
 91     }
 92 
 93     /// <summary>
 94     /// 判断字符串中是否包含半角字符
 95     /// </summary>
 96     /// <param name="str"></param>
 97     /// <returns></returns>
 98     public static bool HasDbcCase(string str)
 99     {
100         return CountDbcCase(str) > 0;
101     }
102 
103     /// <summary>
104     /// 判断字符串中是否符合邮箱格式
105     /// </summary>
106     /// <param name="str"></param>
107     /// <returns></returns>
108     public static bool IsEmail(string str)
109     {
110         return Regex.IsMatch(str, @"^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$");
111     }
112 }