blocks|key|1453323|text|(2009+%25+100).ToString("00");|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1453324|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>(2009 % 100).ToString("00");
</code></pre>

blocks|key|1177569|text|我99.9%25肯定这是不可能做到的，除非你把年份存储在一个DateTime中...|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1177570|entityMap^0|S|8|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

I'm 99.9% certain this cannot be done unless you have the year stored in a <code>DateTime</code>...

blocks|key|1453348|text|我真的认为你应该这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1453349|String+s+=+"2009";
s.Substring(s.Length+-+2);|code-block|syntax|javascript|1453350|没有办法格式化该字符串以限制您想要的位数。|1453351|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I really think that you ought to do this:

<pre><code>String s = "2009";
s.Substring(s.Length - 2);
</code></pre>

There is no way to format that string to restrict the number of digits like you want to.

blocks|key|1453364|text|我看到了这个问题，冒着被激怒的风险，我想指出这一点：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1453365|如果您正在格式化一个DateTime，或者您有一个要格式化的日期，您可以简单地执行一个ToString("yy")。同样的，如果你只需要处理几年。|1453366|DateTime+dt+=+new+DateTime(2009,+1,+1);+//any+DateTime+would+do,+really.
return+dt.ToString("yy");+//"09"|code-block|syntax|javascript|1453367|但是，如果这是某种奇怪的泛型，我想要字符串业务的最后两个字符，最快的路径是：|1453368|string+numString+=+someInt.ToString();
return+numString.Substring(numString.Length+-+2);|1453369|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I saw the question, and at the risk of being flamed, I want to point this out:

If you're formatting a DateTime, or you've got a Date you're formatting you can simply do a ToString("yy"). Likewise if you're only dealing with years.

<pre><code>DateTime dt = new DateTime(2009, 1, 1); //any DateTime would do, really.
return dt.ToString("yy"); //"09"
</code></pre>

but if this is some weird generic I want the last two characters of a string business, the fastest route is:

<pre><code>string numString = someInt.ToString();
return numString.Substring(numString.Length - 2);
</code></pre>

blocks|key|151725|text|如果您对更复杂的内容有合理的需求，您可以随时创建自己的自定义格式提供程序：http://msdn.microsoft.com/en-us/library/system.iformatprovider.aspx|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|151726|然后，您可以将字符串格式化为您想要的任何模式，并适当地封装功能以便重用。|151727|下面是一个示例：|151728|class+Program
{
++++static+void+Main(string[]+args)
++++{
++++++++var+date+=+"2009";

++++++++Console.Write(string.Format(new+CustomFormatProvider(),+"{0:YY}",+date));

++++++++Console.ReadKey();
++++}

++++public+class+CustomFormatProvider+:+IFormatProvider,+ICustomFormatter
++++{
++++++++public+object+GetFormat(Type+formatType)
++++++++{
++++++++++++if+(formatType+==+typeof(ICustomFormatter))
++++++++++++++++return+this;
++++++++++++else
++++++++++++++++return+null;
++++++++}

++++++++public+string+Format(string+fmt,+object+arg,+IFormatProvider+formatProvider)
++++++++{
++++++++++++string+year+=+arg.ToString();
++++++++++++string+result+=+string.Empty;
++++++++++++fmt+=+fmt.Trim().ToUpper();

++++++++++++if+(fmt.Equals("YY"))+
++++++++++++++++return+year.Substring(2,+2);
++++++++++++else+if+(fmt.Equals("YYYY"))
++++++++++++++++return+year;
++++++++++++else+
++++++++++++++++throw+new+FormatException(String.Format("{0}+is+not+a+valid+format+string.",+fmt));

++++++++}
++++}
}|code-block|syntax|javascript|151729|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/system.iformatprovider.aspx^0|11|1V|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|6|7|Y|8|@]|9|@]|C|$]]|$1|F|3|G|5|6|7|Z|8|@]|9|@]|C|$]]|$1|H|3|I|5|J|7|10|8|@]|9|@]|C|$K|L]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

If you have a legitimate need for something more sophisticated, you can always create your own custom format provider: <a href="http://msdn.microsoft.com/en-us/library/system.iformatprovider.aspx" rel="nofollow noreferrer">http://msdn.microsoft.com/en-us/library/system.iformatprovider.aspx</a>

You can then format your strings in whatever pattern you want, and properly encapsulate the functionality for reuse.

Here is an example:

<pre><code>class Program
{
 static void Main(string[] args)
 {
 var date = "2009";

 Console.Write(string.Format(new CustomFormatProvider(), "{0:YY}", date));

 Console.ReadKey();
 }

 public class CustomFormatProvider : IFormatProvider, ICustomFormatter
 {
 public object GetFormat(Type formatType)
 {
 if (formatType == typeof(ICustomFormatter))
 return this;
 else
 return null;
 }

 public string Format(string fmt, object arg, IFormatProvider formatProvider)
 {
 string year = arg.ToString();
 string result = string.Empty;
 fmt = fmt.Trim().ToUpper();

 if (fmt.Equals("YY")) 
 return year.Substring(2, 2);
 else if (fmt.Equals("YYYY"))
 return year;
 else 
 throw new FormatException(String.Format("{0} is not a valid format string.", fmt));

 }
 }
}
</code></pre>

I know I can use substring or other methods, but I'm just curious if there is something to replace the ? below to have it return "09"

<pre><code>String.Format({0:?}, 2009);
</code></pre>

btw, I came across a good cheat sheet while trying to figure this out...
<a href="http://john-sheehan.com/blog/wp-content/uploads/msnet-formatting-strings.pdf" rel="nofollow noreferrer">http://john-sheehan.com/blog/wp-content/uploads/msnet-formatting-strings.pdf</a>

Number format string to show only right 2 digits

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我知道我可以使用子字符串或其他方法，但我只是好奇是否有什么东西可以替代？下面让它返回"09“String.Format({0:?}, 2009);顺便说一句，我在尝试解决这个问题时遇到了一个很好的小抄…

问数字格式字符串，仅显示右2位数字
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