C# 字符串格式化_C# 字符串格式化整理

ゝ一纸荒年。 2022-12-24 13:52 249阅读 0赞

**一、C\# 字符串格式化\_C\# 字符串格式化整理**

使用方式1:  **xxx.ToString(xxxx)**

使用方式2：**string.Format(xxxx,xxx) **

**1、占位符格式化**

零占位符：固定位数，不足补充0

数字占位符：最小化数字展示，“\#\#”格式字符串使得值被舍入到小数点前最近的数字，其中零总被舍去。

空格占位符

string.Format("\{0,-50\}", theObj);//格式化成50个字符，原字符左对齐，不足则补空格  
string.Format("\{0,50\}", theObj);//格式化成50个字符，原字符右对齐，不足则补空格

string.Format("{0:0000.00}", 12394.039) 结果为：12394.04
    
    string.Format("{0:0000.00}", 194.039) 结果为：0194.04
    
    string.Format("{0:###.##}", 12394.039) 结果为：12394.04
    
    string.Format("{0:####.#}", 194.039) 结果为：194

自定义数值格式：

<table> 
 <thead> 
  <tr> 
   <th>Specifier</th> 
   <th>Type</th> 
   <th>Example</th> 
   <th>Output (Passed Double 1500.42)</th> 
   <th>Note</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>0</td> 
   <td>Zero placeholder</td> 
   <td>{0:00.0000}</td> 
   <td>1500.4200</td> 
   <td>Pads with zeroes.</td> 
  </tr> 
  <tr> 
   <td>#</td> 
   <td>Digit placeholder</td> 
   <td>{0:(#).##}</td> 
   <td>(1500).42</td> 
   <td>&nbsp;</td> 
  </tr> 
  <tr> 
   <td>.</td> 
   <td>Decimal point</td> 
   <td>{0:0.0}</td> 
   <td>1500.4</td> 
   <td>&nbsp;</td> 
  </tr> 
  <tr> 
   <td>,</td> 
   <td>Thousand separator</td> 
   <td>{0:0,0}</td> 
   <td>1,500</td> 
   <td>Must be between two zeroes.</td> 
  </tr> 
  <tr> 
   <td>,.</td> 
   <td>Number scaling</td> 
   <td>{0:0,.}</td> 
   <td>2</td> 
   <td>Comma adjacent to Period scales by 1000.</td> 
  </tr> 
  <tr> 
   <td><span style="color:#3399ea;">%</span></td> 
   <td><span style="color:#3399ea;">Percent</span></td> 
   <td><span style="color:#3399ea;">{0:0%}</span></td> 
   <td><span style="color:#3399ea;">150042%</span></td> 
   <td><span style="color:#3399ea;">Multiplies by 100, adds % sign.</span></td> 
  </tr> 
  <tr> 
   <td>e</td> 
   <td>Exponent placeholder</td> 
   <td>{0:00e+0}</td> 
   <td>15e+2</td> 
   <td>Many exponent formats available.</td> 
  </tr> 
  <tr> 
   <td>;</td> 
   <td>Group separator see below</td> 
   <td>&nbsp;</td> 
   <td>&nbsp;</td> 
   <td>&nbsp;</td> 
  </tr> 
 </tbody> 
</table>

**百分比格式化：**

Console.WriteLine((0.1234).ToString("P0"));//12%
    Console.WriteLine((0.1234).ToString("P"));//12.34%
    Console.WriteLine(string.Format("{0:P2}",0.12345));//12.35%

**2. 常用数字类型格式化：**

<table> 
 <thead> 
  <tr> 
   <th>字符串格式符号</th> 
   <th>说明</th> 
   <th>代码示例</th> 
   <th>输出</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>C</td> 
   <td>货币</td> 
   <td>2.5.ToString(“C”)</td> 
   <td>￥2.50</td> 
  </tr> 
  <tr> 
   <td>D</td> 
   <td>十进制</td> 
   <td>25.ToString(“D5”)</td> 
   <td>00025</td> 
  </tr> 
  <tr> 
   <td>E</td> 
   <td>科学计数法</td> 
   <td>25000.ToString(“E”)</td> 
   <td>2.500000E+005</td> 
  </tr> 
  <tr> 
   <td>F</td> 
   <td>固定小数点位数</td> 
   <td>25.ToString(“F2”)</td> 
   <td>25.00</td> 
  </tr> 
  <tr> 
   <td>G</td> 
   <td>常规</td> 
   <td>2.5.ToString(“G”)</td> 
   <td>2.5</td> 
  </tr> 
  <tr> 
   <td>N</td> 
   <td>数值</td> 
   <td>2500000.ToString(“N”)</td> 
   <td>2,500,000.00</td> 
  </tr> 
  <tr> 
   <td>X</td> 
   <td>十六进制</td> 
   <td>255.ToString(“X”)</td> 
   <td>FF</td> 
  </tr> 
 </tbody> 
</table>

基本数字格式说明符：

<table> 
 <thead> 
  <tr> 
   <th>Specifier</th> 
   <th>Type</th> 
   <th>Format</th> 
   <th>Output (Passed Double 1.42)</th> 
   <th>Output (Passed Int -12400)</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>c</td> 
   <td>Currency</td> 
   <td>{0:c}</td> 
   <td>$1.42</td> 
   <td>-$12,400</td> 
  </tr> 
  <tr> 
   <td>d</td> 
   <td>Decimal (Whole number)</td> 
   <td>{0:d}</td> 
   <td>System.FormatException</td> 
   <td>-12400</td> 
  </tr> 
  <tr> 
   <td>e</td> 
   <td>Scientific</td> 
   <td>{0:e}</td> 
   <td>1.420000e+000</td> 
   <td>-1.240000e+004</td> 
  </tr> 
  <tr> 
   <td>f</td> 
   <td>Fixed point</td> 
   <td>{0:f}</td> 
   <td>1.42</td> 
   <td>-12400.00</td> 
  </tr> 
  <tr> 
   <td>g</td> 
   <td>General</td> 
   <td>{0:g}</td> 
   <td>1.42</td> 
   <td>-12400</td> 
  </tr> 
  <tr> 
   <td>n</td> 
   <td>Number with commas for thousands</td> 
   <td>{0:n}</td> 
   <td>1.42</td> 
   <td>-12,400</td> 
  </tr> 
  <tr> 
   <td>r</td> 
   <td>Round trippable</td> 
   <td>{0:r}</td> 
   <td>1.42</td> 
   <td>System.FormatException</td> 
  </tr> 
  <tr> 
   <td>x</td> 
   <td>Hexadecimal</td> 
   <td>{0:x4}</td> 
   <td>System.FormatException</td> 
   <td>cf90</td> 
  </tr> 
 </tbody> 
</table>

**3.时间类型格式化：**

稍后见另一篇文章

## [C\# 字符串拼接整理\_C\#字符串拼接方式整理][C_ _C] ##

## [C\# 项目结构整理\_.Net 项目结构整理][C_ _.Net] ##

## [C\#中float, double的计算存在精度问题][C_float_ double] ##

[C_ _C]: https://blog.csdn.net/u011127019/article/details/110281852
[C_ _.Net]: https://blog.csdn.net/u011127019/article/details/110272630
[C_float_ double]: https://blog.csdn.net/u011127019/article/details/108531774