最快要去除串字符的方式 [英] Fastest way to remove chars from string
问题描述
我有一个字符串从中我必须删除以下字符：'\ r'，'\ N'和'\ T'。 我曾尝试三种不同的删除这些字符的方法和基准他们，所以我可以得到最快的解决方案。
以下是方法和有执行时间，当我跑他们的100万倍：
这应该是最快的解决方案，如果我有1或2个字符删除。但正如我把更多的字符，它开始采取更多的时间
海峡= str.Replace（\ r，即的String.Empty）.Replace（\ N的String.Empty）.Replace（\ t的，的String.Empty ）;
执行时间= 1695
有关1或2个字符，这是慢然后与string.replace，但对于3字符它表现出更好的性能。
的String []分割= str.Split（新的char [] {'\ T'，'\ r'，'\ N'}，StringSplitOptions.None）;
海峡= split.Aggregate＆LT;字符串＆GT;（（STR1，STR2）=＆GT; STR1 + STR2）;
执行时间= 1030
所有的最慢的，即使有1字符。也许我经常EX pression是不是最好的。
海峡= Regex.Replace（STR，[\ r \ñ\ T]的String.Empty，RegexOptions.Compiled）;
执行时间= 3500
以上是三种解决方案，我想出了。有没有更好的，更快的解决方案，任何人都知道这里，或者任何改善，我可以在这个code吗？
字符串，我用的标杆：
StringBuilder的建设者=新的StringBuilder（）;
builder.AppendFormat("{0}\r\n{1}\t\t\t\r\n{2}\t\r\n{3}\r\n{4}\t\t\r\n{5}\r\n{6}\r\n{7}\r\n{8}\r\n{9}",
选择 ，
[Extent1]。[客户] AS [客户]，
[Extent1]。[NameStyle] AS [NameStyle]，
[Extent1]。[标题]（职称），
[Extent1] [名字] AS [名字]，
[Extent1]。[MiddleName] AS [MiddleName]，
[Extent1] [姓氏] AS [姓氏]，
[Extent1]。[说明] AS [后缀]，
[Extent1]。[公司名称] AS [公司名称]，
[Extent1] [业务员] AS [业务员]）;
字符串str = builder.ToString（）;
下面是尤伯杯快速不安全的版本，版本2。
公共静态不安全字符串StripTabsAndNewlines（字符串s）
{
INT LEN = s.Length;
字符* newChars = stackalloc的char [LEN]
字符* currentChar = newChars;
的for（int i = 0; I＆LT; LEN ++ I）
{
焦炭C = S [I]
开关（三）
{
案'\ r'：
案'\ n'的
案\ t：
继续;
默认：
* currentChar ++ = C;
打破;
}
}
返回新的字符串（newChars，0，（INT）（currentChar - newChars））;
}
和这里的基准测试（时间，脱衣百万串MS）
cornerback84的与string.replace：9433 安迪·韦斯特的String.Concat：4756 AviJ的字符数组：1374 马特豪厄尔斯'字符指针：1163
I have a string from which I have to remove following char: '\r', '\n', and '\t'. I have tried three different ways of removing these char and benchmarked them so I can get the fastest solution.
Following are the methods and there execution time when I ran them 1000000 times:
It should be fastest solution if I have 1 or 2 char to remove. But as I put in more char, it starts to take more time
str = str.Replace("\r", string.Empty).Replace("\n", string.Empty).Replace("\t", string.Empty);
Execution time = 1695
For 1 or 2 char, this was slower then String.Replace, but for 3 char it showed better performance.
string[] split = str.Split(new char[] { '\t', '\r', '\n' }, StringSplitOptions.None);
str = split.Aggregate<string>((str1, str2) => str1 + str2);
Execution time = 1030
The slowest of all, even with 1 char. Maybe my regular expression is not the best.
str = Regex.Replace(str, "[\r\n\t]", string.Empty, RegexOptions.Compiled);
Execution time = 3500
These are the three solutions I came up with. Is there any better and faster solution that anyone here know, or any improvements I can do in this code?
String that I used for benchmarking:
StringBuilder builder = new StringBuilder();
builder.AppendFormat("{0}\r\n{1}\t\t\t\r\n{2}\t\r\n{3}\r\n{4}\t\t\r\n{5}\r\n{6}\r\n{7}\r\n{8}\r\n{9}",
"SELECT ",
"[Extent1].[CustomerID] AS [CustomerID], ",
"[Extent1].[NameStyle] AS [NameStyle], ",
"[Extent1].[Title] AS [Title], ",
"[Extent1].[FirstName] AS [FirstName], ",
"[Extent1].[MiddleName] AS [MiddleName], ",
"[Extent1].[LastName] AS [LastName], ",
"[Extent1].[Suffix] AS [Suffix], ",
"[Extent1].[CompanyName] AS [CompanyName], ",
"[Extent1].[SalesPerson] AS [SalesPerson], ");
string str = builder.ToString();
Here's the uber-fast unsafe version, version 2.
public static unsafe string StripTabsAndNewlines(string s)
{
int len = s.Length;
char* newChars = stackalloc char[len];
char* currentChar = newChars;
for (int i = 0; i < len; ++i)
{
char c = s[i];
switch (c)
{
case '\r':
case '\n':
case '\t':
continue;
default:
*currentChar++ = c;
break;
}
}
return new string(newChars, 0, (int)(currentChar - newChars));
}
And here are the benchmarks (time to strip 1000000 strings in ms)
cornerback84's String.Replace: 9433
Andy West's String.Concat: 4756
AviJ's char array: 1374
Matt Howells' char pointers: 1163
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