在 C# 上的最后一个点上断开字符串的最佳方法
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Best way to break a string on the last dot on C#
提问by pupeno
What would be the best way and more idiomatic to break a string into two at the place of the last dot? Basically separating the extension from the rest of a path in a file path or URL. So far what I'm doing is Split(".") and then String.Join(".") of everything but the last part. Sounds like using a bazooka to kill flies.
在最后一个点的位置将字符串分成两部分的最佳方法和更惯用的方法是什么？基本上将扩展名与文件路径或 URL 中路径的其余部分分开。到目前为止，我正在做的是 Split(".") 然后 String.Join(".") 除了最后一部分之外的所有内容。听起来像是用火箭筒杀死苍蝇。
采纳答案by Marc Gravell
If you want performance, something like:
如果你想要性能，比如：
string s = "a.b.c.d";
int i = s.LastIndexOf('.');
string lhs = i < 0 ? s : s.Substring(0,i),
rhs = i < 0 ? "" : s.Substring(i+1);
回答by Philippe Leybaert
You could use Path.GetFilenameWithoutExtension()
你可以使用Path.GetFilenameWithoutExtension()
or if that won't work for you:
或者如果这对您不起作用：
int idx = filename.LastIndexOf('.');
if (idx >= 0)
filename = filename.Substring(0,idx);
回答by Wayne
The string method LastIndexOfmaybe of some use to you here.
字符串方法LastIndexOf在这里可能对您有用。
But the Path or FileInfo operators will be better suited for filename based operations.
但是 Path 或 FileInfo 运算符将更适合基于文件名的操作。
回答by Markus Olsson
I think what you're really looking for is Path.GetFileNameWithoutExtension Method (System.IO)but just for the heck of it:
我认为你真正要找的是Path.GetFileNameWithoutExtension Method (System.IO)但只是为了它：
string input = "foo.bar.foobar";
int lastDotPosition = input.LastIndexOf('.');
if (lastDotPosition == -1)
{
Console.WriteLine("No dot found");
}
else if (lastDotPosition == input.Length - 1)
{
Console.WriteLine("Last dot found at the very end");
}
else
{
string firstPart = input.Substring(0, lastDotPosition);
string lastPart = input.Substring(lastDotPosition + 1);
Console.WriteLine(firstPart);
Console.WriteLine(lastPart);
}
回答by Patrick McDonald
To get the path without the extension, use
要获取没有扩展名的路径，请使用
System.IO.Path.GetFileNameWithoutExtension(fileName)
and to get the extenstion (including the dot), use
并获得扩展名（包括点），使用
Path.GetExtension(fileName)
EDIT:
编辑：
Unfortunately GetFileNameWithoutExtension strips off the leading path, so instead you could use:
不幸的是 GetFileNameWithoutExtension 去掉了前导路径，所以你可以使用：
if (path == null)
{
return null;
}
int length = path.LastIndexOf('.');
if (length == -1)
{
return path;
}
return path.Substring(0, length);
回答by Aamir
Path.GetExtension()should help you.
Path.GetExtension()应该可以帮助你。
回答by Mark
What about using the LastIndexOf method which returns the last found position of a character. Then you can use Substring to extract what you want.
使用 LastIndexOf 方法返回最后找到的字符位置怎么样。然后您可以使用 Substring 来提取您想要的内容。
回答by sharptooth
String.LastIndexOf will return you the position of the dot if it ever exists in the string. You can then String.Substring methods to split the string.
String.LastIndexOf 将返回点的位置，如果它曾经存在于字符串中。然后您可以使用 String.Substring 方法来拆分字符串。
回答by Ratnesh Maurya
You can use string's method
您可以使用字符串的方法
LastIndexOf and substring to acomplish the task.
LastIndexOf 和 substring 来完成任务。
