常用的正規表達示-統計

• 統計字串中內某字元或字串出現次數
  

  /*
  * JavaScript 
  * 找出cloudchen有幾個c
  */
  var str =  "cloudchen"
  var find = "c";
  var reg = new RegExp(find,"g")
  var result = str.match(reg);
  var count = (result)?result.length:0;
  console.log('共：%d次',count);

  reference: JavaScript 統計字串中內某字元或字串出現次數
  
• 統計字串中內某字元或字串出現次數
  去-,:,空白,由於"-"是保留字，所以在前面要加\
  

  //C#.Net
  System.Text.RegularExpressions.Regex reg = new System.Text.RegularExpressions.Regex(@"[:|\-| ]");
  string datetime = "2009-01-02 03:04:05";
  datetime = reg.Replace(datetime, "");
  Console.WriteLine(datetime); //輸出20090102030405

  .Net的Regex位於System.Text.RegularExpressions之下

References:
Regular Expression (RegExp) in JavaScript 還可以直接測試
regular language 說明表格