blocks|key|3034002|text|如果你真的关心，你可以分析它。编写一个多次迭代的循环，看看会发生什么。然而，这可能不是应用程序中的瓶颈，而TrimStart似乎在语义上是最正确的。在优化之前，努力让代码具有可读性。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3034003|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

You could profile it, if you really cared. Write a loop of many iterations and see what happens. Chances are, however, that this is not the bottleneck in your application, and TrimStart seems the most semantically correct. Strive to write code readably before optimizing.

blocks|key|302722|text|我猜Remove和Substring会并列第一，因为它们都会吞噬字符串的固定大小部分，而TrimStart会从左侧扫描每个字符，然后必须执行与其他两种方法完全相同的工作。不过，说真的，这简直是吹毛求疵。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|302723|entityMap^0|2|6|9|9|18|9|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|O|8|@]|D|@]|E|$]]]|G|$]]

I'd guess that <code>Remove</code> and <code>Substring</code> would tie for first place, since they both slurp up a fixed-size portion of the string, whereas <code>TrimStart</code> does a scan from the left with a test on each character and then has to perform exactly the same work as the other two methods. Seriously, though, this is splitting hairs.

blocks|key|302732|text|第二个选项实际上与其他选项不同-如果字符串是“/foo”，它将变成"foo“而不是"//foo”。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|302733|第一个选项比第三个选项需要更多的工作才能理解-我认为Substring选项是最常见和可读性最好的。|offset|length|style|CODE|302734|(显然，它们中的每一个作为单独的语句都不会做任何有用的事情-您需要将结果赋给一个变量，可能是data本身。)|302735|我不会在这里考虑性能，除非它确实成为您的问题-在这种情况下，您知道的唯一方法就是拥有测试用例，然后很容易为每个选项运行这些测试用例并比较结果。我希望Substring在这里可能是最快的，因为Substring总是从原始输入的单个块创建字符串，而Remove至少必须潜在地将开始块和结束块粘合在一起。|302736|entityMap^0|0|Q|9|0|1A|4|0|22|9|2N|9|3E|6|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@$D|P|E|Q|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|R|8|@$D|S|E|T|F|G]]|9|@]|A|$]]|$1|J|3|K|5|6|7|U|8|@$D|V|E|W|F|G]|$D|X|E|Y|F|G]|$D|Z|E|10|F|G]]|9|@]|A|$]]|$1|L|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|M|$]]

The second option really isn't the same as the others - if the string is "///foo" it will become "foo" instead of "//foo".

The first option needs a bit more work to understand than the third - I would view the <code>Substring</code> option as the most common and readable.

(Obviously each of them as an individual statement won't do anything useful - you'll need to assign the result to a variable, possibly <code>data</code> itself.)

I wouldn't take performance into consideration here unless it was actually becoming a problem for you - in which case the only way you'd know would be to have test cases, and then it's easy to just run those test cases for each option and compare the results. I'd expect <code>Substring</code> to probably be the fastest here, simply because <code>Substring</code> always ends up creating a string from a single chunk of the original input, whereas <code>Remove</code> has to at least potentially glue together a start chunk and an end chunk.

blocks|key|3034101|text|我知道这是一个超级优化的领域，但这似乎是踢BenchmarkDotNet车轮的好借口。这个测试的结果(甚至在.NET核心上)是Substring比Remove略快，在这个样本测试中：Remove的速度是19.37+is比22.52+is。因此速度提高了约16%25。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3034102|using+System;
using+BenchmarkDotNet.Attributes;

namespace+BenchmarkFun
{
++++public+class+StringSubstringVsRemove
++++{
++++++++public+readonly+string+SampleString+=+"+My+name+is+Daffy+Duck.";

++++++++[Benchmark]
++++++++public+string+StringSubstring()+=>+SampleString.Substring(1);

++++++++[Benchmark]
++++++++public+string+StringRemove()+=>+SampleString.Remove(0,+1);

++++++++public+void+AssertTestIsValid()
++++++++{
++++++++++++string+subsRes+=+StringSubstring();
++++++++++++string+remvRes+=+StringRemove();

++++++++++++if+(subsRes+==+null
++++++++++++++++%7C%7C+subsRes.Length+!=+SampleString.Length+-+1
++++++++++++++++%7C%7C+subsRes+!=+remvRes)+{
++++++++++++++++throw+new+Exception("INVALID+TEST!");
++++++++++++}
++++++++}
++++}

++++class+Program
++++{
++++++++static+void+Main()
++++++++{
++++++++++++//+let's+make+sure+test+results+are+really+equal+/+valid
++++++++++++new+StringSubstringVsRemove().AssertTestIsValid();

++++++++++++var+summary+=+BenchmarkRunner.Run<StringSubstringVsRemove>();
++++++++}
++++}
}|code-block|syntax|javascript|3034103|结果：|3034104|BenchmarkDotNet=v0.11.4,+OS=Windows+10.0.17763.253+(1809/October2018Update/Redstone5)
Intel+Core+i7-6700HQ+CPU+2.60GHz+(Skylake),+1+CPU,+8+logical+and+4+physical+cores
.NET+Core+SDK=3.0.100-preview-010184
++[Host]+++++:+.NET+Core+3.0.0-preview-27324-5+(CoreCLR+4.6.27322.0,+CoreFX+4.7.19.7311),+64bit+RyuJIT
++DefaultJob+:+.NET+Core+3.0.0-preview-27324-5+(CoreCLR+4.6.27322.0,+CoreFX+4.7.19.7311),+64bit+RyuJIT

%7C++++++++++Method+%7C+++++Mean+%7C+++++Error+%7C++++StdDev+%7C
%7C----------------+%7C---------:%7C----------:%7C----------:%7C
%7C+StringSubstring+%7C+19.37+ns+%7C+0.3940+ns+%7C+0.3493+ns+%7C
%7C++++StringRemove+%7C+22.52+ns+%7C+0.4062+ns+%7C+0.3601+ns+%7C|3034105|entityMap^0|L|F|1R|9|21|6|2J|6|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|Z|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|10|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|P|$]]

I know this is hyper-optimization land, but it seemed like a good excuse to kick the wheels of <code>BenchmarkDotNet</code>. The result of this test (on .NET Core even) is that <code>Substring</code> is ever so slightly faster than <code>Remove</code>, in this sample test: 19.37ns vs 22.52ns for <code>Remove</code>. So some ~16% faster.

<pre><code>using System;
using BenchmarkDotNet.Attributes;

namespace BenchmarkFun
{
 public class StringSubstringVsRemove
 {
 public readonly string SampleString = " My name is Daffy Duck.";

 [Benchmark]
 public string StringSubstring() =&gt; SampleString.Substring(1);

 [Benchmark]
 public string StringRemove() =&gt; SampleString.Remove(0, 1);

 public void AssertTestIsValid()
 {
 string subsRes = StringSubstring();
 string remvRes = StringRemove();

 if (subsRes == null
 || subsRes.Length != SampleString.Length - 1
 || subsRes != remvRes) {
 throw new Exception("INVALID TEST!");
 }
 }
 }

 class Program
 {
 static void Main()
 {
 // let's make sure test results are really equal / valid
 new StringSubstringVsRemove().AssertTestIsValid();

 var summary = BenchmarkRunner.Run&lt;StringSubstringVsRemove&gt;();
 }
 }
}
</code></pre>

Results:

<pre><code>BenchmarkDotNet=v0.11.4, OS=Windows 10.0.17763.253 (1809/October2018Update/Redstone5)
Intel Core i7-6700HQ CPU 2.60GHz (Skylake), 1 CPU, 8 logical and 4 physical cores
.NET Core SDK=3.0.100-preview-010184
 [Host] : .NET Core 3.0.0-preview-27324-5 (CoreCLR 4.6.27322.0, CoreFX 4.7.19.7311), 64bit RyuJIT
 DefaultJob : .NET Core 3.0.0-preview-27324-5 (CoreCLR 4.6.27322.0, CoreFX 4.7.19.7311), 64bit RyuJIT

| Method | Mean | Error | StdDev |
|---------------- |---------:|----------:|----------:|
| StringSubstring | 19.37 ns | 0.3940 ns | 0.3493 ns |
| StringRemove | 22.52 ns | 0.4062 ns | 0.3601 ns |
</code></pre>

blocks|key|300549|text|在.Net核心中，这也是有效的：|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|300550|data+=+data[1..];|code-block|syntax|javascript|300551|entityMap^0|1|6|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

In .Net Core also this works:
<pre><code>data = data[1..];
</code></pre>

Say we have the following string 

<pre><code>string data= "/temp string";
</code></pre>

If we want to remove the first character <code>/</code> we can do by a lot of ways such as :

<pre><code>data.Remove(0,1);
data.TrimStart('/');
data.Substring(1);
</code></pre>

But, really I don't know which one has the best algorithm and doing that faster.. 
Is there a one that is the best or all are the same ?

Fastest way to remove first char in a String

Windows

假设我们有以下字符串string data= "/temp string";如果我们想要删除第一个字符/，我们可以通过许多方法来实现，例如：data.Remove(0,1);data.TrimStart('/');data.Substring(1);但是，我真的不知道哪一个算法最好，而且做得更快。有没有一个是最好的，还...

问删除字符串中第一个字符的最快方法
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