正则表达式在字符串中查找时间

Question

我正在尝试使用正则表达式从以下字符串中提取时间

Free concert at 8 pm over there
Free concert at 8pm over there
Free concert at 8:30 pm over there
Free concert at 8:30pm over there

有人知道如何在java中使用Regex吗？

我已经尝试了以下（1 [012] | [1-9]）：[0-5] 0-9？（？i）（am | pm）但我不认为它允许以前的单词或后。

谢谢！

Answer 1

试试这个：(?i)at (.+?) over

示例：

String str = "Free concert at 8 pm over there"
        + "Free concert at 8pm over there"
        + "Free concert at 8:30 pm over there"
        + "Free concert at 8:30pm over there";

Pattern p = Pattern.compile("(?i)at (.+?) over");
Matcher m = p.matcher(str);

while( m.find() )
{
    System.out.println(m.group(1));
}

<强>输出：

8 pm
8pm
8:30 pm
8:30pm

另一个（仅限时间，没有/或超过任何其他词）：

(?i)[0-9]{1,2}:??[0-9]{0,2}\\s??(?:am|pm)

但是你不需要group(1)（你可以group(0)或只是group()）！

示例：

String str = "Free concert at 8 pm over there"
        + "Free concert at 8pm over there"
        + "Free concert at 8:30 pm over there"
        + "Free concert at 8:30pm over there";

Pattern p = Pattern.compile("(?i)[0-9]{1,2}:??[0-9]{0,2}\\s??(?:am|pm)");
Matcher m = p.matcher(str);

while( m.find() )
{
    System.out.println(m.group());
}