C# 正则表达式匹配不是特定子字符串的东西
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/42990/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Regex to match against something that is not a specific substring
提问by John Meagher
I am looking for a regex that will match a string that starts with one substring and does not end with a certain substring.
我正在寻找一个正则表达式，它将匹配以一个子字符串开头但不以某个子字符串结尾的字符串。
Example:
例子：
// Updated to be correct, thanks @Apocalisp
^foo.*(?<!bar)$
Should match anything that starts with "foo" and doesn't end with "bar". I know about the [^...] syntax, but I can't find anything that will do that for a string instead of single characters.
应该匹配以“foo”开头且不以“bar”结尾的任何内容。我知道 [^...] 语法，但我找不到任何可以对字符串而不是单个字符执行此操作的内容。
I am specifically trying to do this for Java's regex, but I've run into this before so answers for other regex engines would be great too.
我特别想为 Java 的正则表达式做这件事，但我之前遇到过这个问题，所以其他正则表达式引擎的答案也会很棒。
Thanks to @Kibbee for verifying that this works in C# as well.
感谢 @Kibbee 验证这也适用于 C#。
采纳答案by Apocalisp
I think in this case you want negative lookbehind, like so:
我认为在这种情况下，您需要负面的lookbehind，如下所示：
foo.*(?<!bar)
回答by Sam Hasler
I'm not familiar with Java regex but documentation for the Pattern Classwould suggest you could use (?!X) for a non-capturing zero-width negative lookahead (it looks for something that is not X at that postision, without capturing it as a backreference). So you could do:
我不熟悉 Java 正则表达式，但Pattern Class 的文档建议您可以使用 (?!X) 进行非捕获零宽度负前瞻（它在该位置寻找不是 X 的东西，而不捕获它）作为反向引用）。所以你可以这样做：
foo.*(?!bar) // not correct
Update: Apocalisp's right, you want negative lookbehind. (you're checking that what the .* matches doesn't end with bar)
更新：Apocalisp 是对的，你想要负面的回顾。（您正在检查 .* 匹配的内容不以 bar 结尾）
回答by aku
As other commenters said, you need a negative lookahead. In Java you can use this pattern:
正如其他评论者所说，你需要一个负面的前瞻。在 Java 中，您可以使用此模式：
"^first_string(?!.?second_string)\z"
- ^ - ensures that string starts with first_string
- \z - ensures that string ends with second_string
- (?!.?second_string) - means that first_string can't be followed by second_string
- ^ - 确保字符串以 first_string 开头
- \z - 确保字符串以 second_string 结尾
- (?!.?second_string) - 表示 first_string 后面不能跟 second_string
回答by John Meagher
Verified @Apocalisp's answer using:
使用以下方法验证@Apocalisp 的答案：
import java.util.regex.Pattern;
public class Test {
public static void main(String[] args) {
Pattern p = Pattern.compile("^foo.*(?<!bar)$");
System.out.println(p.matcher("foobar").matches());
System.out.println(p.matcher("fooBLAHbar").matches());
System.out.println(p.matcher("1foo").matches());
System.out.println(p.matcher("fooBLAH-ar").matches());
System.out.println(p.matcher("foo").matches());
System.out.println(p.matcher("foobaz").matches());
}
}
This output the the right answers:
这将输出正确的答案：
false
false
false
true
true
true
