在线时间:8:00-16:00
迪恩网络APP
随时随地掌握行业动态
扫描二维码
关注迪恩网络微信公众号
今天在写代码时突然想起测试经常用Microsoft.VisualBasic.Information.IsNumeric判断 url参数是否为数字时的这个方法的效率
因为数字是字符串是直接使用的,所以不需要转型,也就没有用tryparse 结果一测试吓一跳,这个方法的效率是如此的低,再测试了下tryparse还不错,正则的也比较差, 没什么技术含量,看结果吧: 先拓展下字符串:
code
public static class Common
{ //isDigit public static bool isNumberic1(this string _string) { if (string.IsNullOrEmpty(_string)) return false; foreach (char c in _string) { if (!char.IsDigit(c))//if(c<'0' || c>'9')//最好的方法,在下面测试数据中再加一个0,然后这种方法效率会搞10毫秒左右 return false; } return true; } //vb isnumberic public static bool isNumberic2(this string _string) { return !string.IsNullOrEmpty(_string) && Microsoft.VisualBasic.Information.IsNumeric(_string); } //try parse public static bool isNumberic3(this string _string) { if (string.IsNullOrEmpty(_string)) return false; int i = 0; return int.TryParse(_string, out i); } //try catch public static bool isNumberic4(this string _string) { if (string.IsNullOrEmpty(_string)) return false; try { int.Parse(_string); } catch { return false; } return true; } //regex public static bool isNumberic5(this string _string) { return !string.IsNullOrEmpty(_string) && Regex.IsMatch(_string, "^\\d+$"); } }
测试的代码:
code
class Program
{ static void Main(string[] args) { Test("1234"); Test("1234a"); Test("a1234"); Test(""); Test(null); } static void Test(string str) { bool res1 = false, res2 = false, res3 = false, res4 = false, res5 = false; Stopwatch wat = new Stopwatch(); wat.Start();// for (int i = 1; i < 100000; i++) { res1 = str.isNumberic1(); } wat.Stop(); Console.WriteLine("isDigit {0}:{1},{2}", str, wat.ElapsedMilliseconds, res1); wat.Reset(); wat.Start(); for (int i = 1; i < 100000; i++) { res2= str.isNumberic2(); } wat.Stop(); Console.WriteLine("isNumberic {0}:{1},{2}", str, wat.ElapsedMilliseconds, res2); wat.Reset(); wat.Start(); for (int i = 1; i < 100000; i++) { res3 = str.isNumberic3(); } wat.Stop(); Console.WriteLine("try parse {0}:{1},{2}", str, wat.ElapsedMilliseconds, res3); wat.Reset(); wat.Start(); for (int i = 1; i < 100000; i++) { res4 = str.isNumberic4(); } wat.Stop(); Console.WriteLine("try catch {0}:{1},{2}", str, wat.ElapsedMilliseconds, res4); wat.Reset(); wat.Start(); for (int i = 1; i < 100000; i++) { res5 = str.isNumberic5(); } wat.Stop(); Console.WriteLine("regex {0}:{1},{2}", str, wat.ElapsedMilliseconds, res5); Console.WriteLine(); } }
下面是我本机的测试结果
isDigit 1234:5,True
isNumberic 1234:166,True try parse 1234:21,True try catch 1234:22,True regex 1234:134,True isDigit 1234a:5,False isNumberic 1234a:196,False try parse 1234a:19,False try catch 1234a:5182,False regex 1234a:150,False isDigit a1234:2,False isNumberic a1234:184,False try parse a1234:16,False try catch a1234:5084,False regex a1234:106,False isDigit :1,False isNumberic :0,False try parse :0,False try catch :1,False regex :0,False isDigit :1,False isNumberic :0,False try parse :1,False try catch :1,False regex :0,False
结果:循环判断是否是数字字符效率是最高的
而VisualBasic的方法效率比较低了 顺便测试了下VisualBasic里的left和right方法效率也一样的低,还不及substring的十分之一 所以VisualBasic里虽然有几个方法从名字看来比较好用,实际却比较杯具。 |
请发表评论