C#中的String.Format

 

把doubel保留2位有效數字
double d = 123;
string res = string.Format("{0：F2}",d);
結果是：d = 123.00

 

參考：

string str1 =string.Format("{0:N1}",56789);               //result: 56,789.0string str2 =string.Format("{0:N2}",56789);               //result: 56,789.00string str3 =string.Format("{0:N3}",56789);               //result: 56,789.000string str8 =string.Format("{0:F1}",56789);               //result: 56789.0string str9 =string.Format("{0:F2}",56789);               //result: 56789.00string str11 =(56789 / 100.0).ToString("#.##");           //result: 567.89string str12 =(56789 / 100).ToString("#.##");             //result: 567 C 或 c貨幣Console.Write("{0:C}", 2.5);  //$2.50Console.Write("{0:C}", -2.5); //($2.50) D 或 d十進位數Console.Write("{0:D5}", 25);  //00025 E 或 e科學型Console.Write("{0:E}", 250000);  //2.500000E+005 F 或 f固定點Console.Write("{0:F2}", 25);  //25.00Console.Write("{0:F0}", 25);  //25 G 或 g常規Console.Write("{0:G}", 2.5);  //2.5 N 或 n數字Console.Write("{0:N}", 2500000);  //2,500,000.00 X 或 x十六進位Console.Write("{0:X}", 250);  //FAConsole.Write("{0:X}", 0xffff);  //FFFF