[英]What's the best way to remove strings?
I need ideas with the best performance to remove/filter strings我需要具有最佳性能的想法来删除/过滤字符串
I have:我有:
string Input = "view('512', 3, 159);";
What's the best performance way to remove "view(" and ");"删除“view(”和“);”的最佳性能方式是什么? and the quotes?和报价? I can do this:我可以做这个:
Input = Input.Replace("view(","").Replace("'","").Replace("\"","").Replace(");","");
but it seems rather inelegant.但它似乎相当不雅。
Input.Split('(')[1].Split(')')[0].Replace("'", "");
it seems rather better似乎更好
I want no do it by using regular expression;我不想通过使用正则表达式来做到这一点; I need make the faster application what I can.我需要尽我所能做出更快的应用程序。 Thanks in advance: :)提前致谢: :)
You could use a simple linq statement:您可以使用简单的 linq 语句:
string Input = "view('512', 3, 159);";
string output = new String( Input.Where( c => Char.IsDigit( c ) || c == ',' ).ToArray() );
Output: 512,3,159 Output:512,3,159
If you want the spaces, just add a check in the where clause.如果你想要空格,只需在 where 子句中添加一个检查。
You could use just a Substring
to remove the view(
and );
您可以只使用Substring
来删除view(
和);
: :
Input.Substring(5, Input.Length - 7)
Other than that it looks reasonably efficient.除此之外,它看起来相当有效。 Plain string operations are pretty well optimised.纯字符串操作得到了很好的优化。
So:所以:
Input =
Input.Substring(5, Input.Length - 7)
.Replace("'", String.Empty)
.Replace("\"", String.Enmpty);
char[] Output = Input.SkipWhile(x => x != '(') // skip before open paren
.Skip(1) // skip open paren
.TakeWhile(x => x != ')') // take everything until close paren
.Where(x => x != '\'' && x != '\"') // except quotes
.ToArray();
return new String(Output);
Hope this helps希望这可以帮助
Regex.Replace("view('512', 3, 159);",@"[(view)';]","")
Use the following:使用以下内容:
System.Text.StringBuilder sb=new System.Text.StringBuilder();
int state=0;
for(var i=0;i<Input.Length;i++){
switch(state){
case 0: // beginning
if(Input[i]=='('){
state=1; // seen left parenthesis
}
break;
case 2: // seen end parentheses
break; // ignore
case 1:
if(Input[i]==')'){
state=2; // seen right parentheses
} else if(Input[i]!='\''){
sb.Append(Input[i]);
}
break;
}
}
Console.WriteLine(sb.ToString());
IndexOf, LastIndexOf, and Substring are probably fastest. IndexOf、LastIndexOf 和 Substring 可能是最快的。
string Input = "view('512', 3, 159);";
int p1 = Input.IndexOf('(');
int p2 = Input.LastIndexOf(')');
Input = Input.Substring (p1 + 1, p2 - p1 - 1);
var result = new string(Input.ToCharArray().
SkipWhile (i => i != '\'').
TakeWhile (i => i != ')').ToArray());
Why don't you want to use regular expressions?为什么不想使用正则表达式? Regular expressions are heavily optimised and will be much faster than any hand written hack.正则表达式经过大量优化,比任何手写的 hack 都要快得多。
This is java (as I run linux and can't run c# as a result), but I hope you get the idea.这是 java (当我运行 linux 并因此无法运行 c# 时),但我希望你明白。
input.replace("view(","").replace("'","").replace("\"","").replace(");","");
A million repetitions of the above runs in about 6 seconds on my computer.在我的电脑上,上述一百万次重复运行大约需要 6 秒。 Whereas, the regular expression below runs in about 2 seconds.然而,下面的正则表达式运行大约 2 秒。
// create java's regex matcher object
// matcher is looking for sequences of digits (valid integers)
Matcher matcher = Pattern.compile("(\\d+)").matcher(s);
StringBuilder builder = new StringBuilder();
// whilst we can find matches append the match plus a comma to a string builder
while (matcher.find()) {
builder.append(matcher.group()).append(',');
}
// return the built string less the last trailing comma
return builder.substring(0, builder.length()-1);
If you want to find valid decimals as well as integers then use the following pattern instead.如果要查找有效的小数和整数,请改用以下模式。 Though it runs slightly slower than the original.虽然它的运行速度比原来的稍慢。
"(\\d+(\\.\\d*)?)"
fastest way would be Input = Input.Substring(5, Input.Length - 7)
最快的方法是Input = Input.Substring(5, Input.Length - 7)
More generic更通用
void Main()
{
string Input = "view('512', 3, 159);";
var statingPoint = Input.IndexOf('(') + 1;
var result = Input.Substring(statingPoint, Input.IndexOf(')') - statingPoint);
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.