java 正则表达式匹配全字 OR 运算符
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/11442179/
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
Regular expression matching whole word OR operator
提问by FirmView
I am trying to match full word from some lines, wanted to know how to use the OR in regex, If i use only one keyword, it works fine. Example,
我正在尝试匹配某些行中的完整单词，想知道如何在正则表达式中使用 OR，如果我只使用一个关键字，它工作正常。例子，
regex = ".*\b" + "KEYWORD1" + "\b.*";
String regex = ".*\b" + "KEYWORD1|KEYWORD2|KEYWORD3" + "\b.*";
for (int i = start; i < end; i++) {
if (lines[i].matches(regex)) {
System.out.println("Matches");
}
}
回答by Kendall Frey
You want:
你要：
String regex = ".*\b(KEYWORD1|KEYWORD2|KEYWORD3)\b.*";
Originally, your regex was being evaluated like this:
最初，您的正则表达式是这样评估的：
.*\bKEYWORD1
|
KEYWORD2
|
KEYWORD3\b.*
But you want:
但你想要：
.*\b
(
KEYWORD1
|
KEYWORD2
|
KEYWORD3
)
\b.*
This cool toolcan help you analyse regexes and find bugs like this one.
这个很酷的工具可以帮助您分析正则表达式并找到像这样的错误。
回答by Andrew Clark
The pipe character |can be used as an OR operator, which is called alternation in regex.
管道符|可以用作 OR 运算符，在正则表达式中称为交替。
To get this to work properly in your example, you just need to create a group around the alternation to be sure that you are doing the OR only on the keywords you are interested in, for example:
要使其在您的示例中正常工作，您只需要围绕交替创建一个组，以确保您仅对您感兴趣的关键字执行 OR，例如：
String regex = ".*\b(KEYWORD1|KEYWORD2|KEYWORD3)\b.*";
What you currently have would mean .*\\bKEYWORD1 OR KEYWORD2 OR KEYWORD3\\b.*.
您目前拥有的将意味着什么.*\\bKEYWORD1 OR KEYWORD2 OR KEYWORD3\\b.*。
