我可以“乘以”一个字符串（在 C# 中）吗？
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Can I "multiply" a string (in C#)?
提问by inspite
Suppose I have a string, for example,
假设我有一个字符串，例如，
string snip = "</li></ul>";
I want to basically write it multiple times, depending on some integer value.
我想基本上写多次，这取决于一些整数值。
string snip = "</li></ul>";
int multiplier = 2;
// TODO: magic code to do this
// snip * multiplier = "</li></ul></li></ul>";
EDIT: I know I can easily write my own function to implement this, I was just wondering if there was some weird string operator that I didn't know about
编辑：我知道我可以轻松编写自己的函数来实现这一点，我只是想知道是否有一些我不知道的奇怪的字符串运算符
采纳答案by Will Dean
In .NET 4 you can do this:
在 .NET 4 中，你可以这样做：
String.Concat(Enumerable.Repeat("Hello", 4))
回答by Tamas Czinege
Unfortunately / fortunately, the string class is sealed so you can't inherit from it and overload the * operator. You can create an extension method though:
不幸/幸运的是，字符串类是密封的，因此您不能从它继承并重载 * 运算符。你可以创建一个扩展方法：
public static string Multiply(this string source, int multiplier)
{
StringBuilder sb = new StringBuilder(multiplier * source.Length);
for (int i = 0; i < multiplier; i++)
{
sb.Append(source);
}
return sb.ToString();
}
string s = "</li></ul>".Multiply(10);
回答by Marc Gravell
You'd have to write a method - of course, with C# 3.0 it could be an extension method:
您必须编写一个方法 - 当然，对于 C# 3.0，它可以是一个扩展方法：
public static string Repeat(this string, int count) {
/* StringBuilder etc */ }
then:
然后：
string bar = "abc";
string foo = bar.Repeat(2);
回答by Chris Ballance
string Multiply(string input, int times)
{
StringBuilder sb = new StringBuilder(input.length * times);
for (int i = 0; i < times; i++)
{
sb.Append(input);
}
return sb.ToString();
}
回答by LukeH
I'm with DrJokepu on this one, but if for some reason you did want to cheat using built-in functionality then you could do something like this:
我和 DrJokepu 一起讨论这个问题，但如果由于某种原因你确实想使用内置功能作弊，那么你可以做这样的事情：
string snip = "</li></ul>";
int multiplier = 2;
string result = string.Join(snip, new string[multiplier + 1]);
Or, if you're using .NET 4:
或者，如果您使用的是 .NET 4：
string result = string.Concat(Enumerable.Repeat(snip, multiplier));
Personally I wouldn't bother though - a custom extension method is much nicer.
就我个人而言，我不会打扰 - 自定义扩展方法要好得多。
回答by Dmitri Nesteruk
Okay, here's my take on the matter:
好的，这是我对这个问题的看法：
public static class ExtensionMethods {
public static string Multiply(this string text, int count)
{
return new string(Enumerable.Repeat(text, count)
.SelectMany(s => s.ToCharArray()).ToArray());
}
}
I'm being a bit silly of course, but when I need to have tabulation in code-generating classes, Enumerable.Repeat does it for me. And yeah, the StringBuilder version is fine, too.
我当然有点傻，但是当我需要在代码生成类中进行制表时， Enumerable.Repeat 会为我做这件事。是的，StringBuilder 版本也很好。
回答by James Curran
Note that if your "string" is only a single character, there is an overload of the string constructor to handle it:
请注意，如果您的“字符串”只是一个字符，则字符串构造函数的重载来处理它：
int multipler = 10;
string TenAs = new string ('A', multipler);
回答by user51710
Just for the sake of completeness - here is another way of doing this:
只是为了完整起见 - 这是另一种方法：
public static string Repeat(this string s, int count)
{
var _s = new System.Text.StringBuilder().Insert(0, s, count).ToString();
return _s;
}
I think I pulled that one from Stack Overflow some time ago, so it is not my idea.
我想我前段时间从 Stack Overflow 中提取了那个，所以这不是我的主意。
回答by Jronny
Here's my take on this just for future reference:
这是我对此的看法，仅供将来参考：
/// <summary>
/// Repeats a System.String instance by the number of times specified;
/// Each copy of thisString is separated by a separator
/// </summary>
/// <param name="thisString">
/// The current string to be repeated
/// </param>
/// <param name="separator">
/// Separator in between copies of thisString
/// </param>
/// <param name="repeatTimes">
/// The number of times thisString is repeated</param>
/// <returns>
/// A repeated copy of thisString by repeatTimes times
/// and separated by the separator
/// </returns>
public static string Repeat(this string thisString, string separator, int repeatTimes) {
return string.Join(separator, ParallelEnumerable.Repeat(thisString, repeatTimes));
}
回答by Frank Schwieterman
If you have .Net 3.5 but not 4.0, you can use System.Linq's
如果你有 .Net 3.5 但没有 4.0，你可以使用 System.Linq's
String.Concat(Enumerable.Range(0, 4).Select(_ => "Hello").ToArray())
