java 正则表达式从单个组中的java字符串中查找整数或小数？
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/25707779/
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 find integer or decimal from a string in java in a single group?
提问by Mimanshu
I am trying (\d+|\d+\.\d+)on this sample string:
我正在尝试(\d+|\d+\.\d+)这个示例字符串：
Oats 124 0.99 V 1.65
but it is giving me decimal number in different groups when I am using pattern matcher classes in Java.
但是当我在 Java 中使用模式匹配器类时，它给了我不同组中的十进制数。
I want my answers in a single group.
我希望我的答案在一个小组中。
回答by Avinash Raj
You don't need to have a separate patterns for integer and floating point numbers. Just make the decimal part as optional and you could get both type of numbers from a single group.
您不需要为整数和浮点数设置单独的模式。只需将小数部分设为可选，您就可以从一个组中获得两种类型的数字。
(\d+(?:\.\d+)?)
Use the above pattern and get the numbers from group index 1.
使用上述模式并从组索引 1 中获取数字。
Code:
代码：
String s = "Oats 124 0.99 V 1.65";
Pattern regex = Pattern.compile("(\d+(?:\.\d+)?)");
Matcher matcher = regex.matcher(s);
while(matcher.find()){
System.out.println(matcher.group(1));
}
Output:
输出：
124
0.99
1.65
Pattern explanation:
图案说明：
()capturing group .\d+matches one or more digits.(?:)Non-capturing group.(?:\.\d+)?Matches a dot and the following one or more digits.?after the non-capturing group makes the whole non-capturing group as optional.
OR
或者
Your regex will also work only if you change the order of the patterns.
仅当您更改模式的顺序时，您的正则表达式也将起作用。
(\d+\.\d+|\d+)
回答by walid toumi
Try this pattern:
试试这个模式：
\d+(?:\.\d+)?
Edit:
\d+ match 1 or more digit
(?: non capturing group (optional)
\. '.' character
\d+ 1 or more digit
)? Close non capturing group
回答by Adam
Question not entirely clear, but the first problem I see is . is a magic character in regex meaning any character. You need to escape it with as . There are lots of regex cheat sheets out there, for example JavaScript Regex Cheatsheet
问题不完全清楚，但我看到的第一个问题是 . 是正则表达式中的魔法字符，表示任何字符。你需要用 as 来逃避它。有很多正则表达式备忘单，例如JavaScript Regex Cheatsheet
(\d+|\d+\.\d+)
