得到HH: mm:ss，mm:ss regex

Question

我有一个字符串，我想在那里提取一个时间戳。时间戳可以在字符串中的任何位置，而时间戳可以是不同的长度。想想youtube视频时间戳吧。

下面是一个例子

从你的27:19:45经历k-12中，你会为教育而改变什么？#改变

我想抽出27:19:45。但是，其他字符串只能包含MM:SS。

我能想到的是

​

const timeRegex = /(?:(?:([01]?\d|2[0-3]):)?([0-5]?\d):)?([0-5]?\d)/gm;

​

当我运行这个正则表达式时，它也会得到字符串的k-12部分中的12，这是我不想要的。

抱歉我删除了秒部分。如果只是几秒钟，它就会有0:12。

Answer 1

使用

(?<!\S)(?:(?:(\d{1,2}):)?([0-5]?\d):)?([0-5]?\d)(?!\S)

见正则证明。

在您的表达式中，您需要使MM部分成为强制的。

解释

--------------------------------------------------------------------------------
  (?<!                     look behind to see if there is not:
--------------------------------------------------------------------------------
    \S                       non-whitespace (all but \n, \r, \t, \f,
                             and " ")
--------------------------------------------------------------------------------
  )                        end of look-behind
--------------------------------------------------------------------------------
  (?:                      group, but do not capture (optional
                           (matching the most amount possible)):
--------------------------------------------------------------------------------
    (?:                      group, but do not capture (optional
                             (matching the most amount possible)):
--------------------------------------------------------------------------------
      (                        group and capture to \1:
--------------------------------------------------------------------------------
        \d{1,2}                  digits (0-9) (between 1 and 2 times
                                 (matching the most amount possible))
--------------------------------------------------------------------------------
      )                        end of \1
--------------------------------------------------------------------------------
      :                        ':'
--------------------------------------------------------------------------------
    )?                       end of grouping
--------------------------------------------------------------------------------
    (                        group and capture to \2:
--------------------------------------------------------------------------------
      [0-5]?                   any character of: '0' to '5' (optional
                               (matching the most amount possible))
--------------------------------------------------------------------------------
      \d                       digits (0-9)
--------------------------------------------------------------------------------
    )                        end of \2
--------------------------------------------------------------------------------
    :                        ':'
--------------------------------------------------------------------------------
  )?                       end of grouping
--------------------------------------------------------------------------------
  (                        group and capture to \3:
--------------------------------------------------------------------------------
    [0-5]?                   any character of: '0' to '5' (optional
                             (matching the most amount possible))
--------------------------------------------------------------------------------
    \d                       digits (0-9)
--------------------------------------------------------------------------------
  )                        end of \3
--------------------------------------------------------------------------------
  (?!                      look ahead to see if there is not:
--------------------------------------------------------------------------------
    \S                       non-whitespace (all but \n, \r, \t, \f,
                             and " ")
--------------------------------------------------------------------------------
  )                        end of look-ahead

Answer 2

这一项应能发挥作用：

const timeRegex = /\d\d:\d\d(:\d\d)?/gm

或者，两个冒号之间的数字可以是一个或两个：

const timeRegex = /\d\d?:\d\d?(:\d\d?)?/gm

测试：

s = "What would you change for education from your 27:09:02 experience k-12? #change'"
-> "What would you change for education from your 27:09:02 experience k-12? #change'"
s.match(/\d\d?:\d\d?(:\d\d?)?/gm)
-> ["27:09:02"]
s = "What would you change for education from your 27:09 experience k-12? #change'"
-> "What would you change for education from your 27:09 experience k-12? #change'"
s.match(/\d\d?:\d\d?(:\d\d?)?/gm)
-> ["27:09"]
s = "What would you change for education from your experience k-12? #change'"
-> "What would you change for education from your experience k-12? #change'"
s.match(/\d\d?:\d\d?(:\d\d?)?/gm)
-> null

Answer 3

您可以使用正向和正向后两种方式，只有在时间的两边都有\s时才能选择。

​

const str =
  "What would you change for education from your 27:19:45 and 12:12 and 11 experience k-12? #change";

const result = str.match(/(?<=\s)(\d\d:?)+(?=\s)/g);
console.log(result);

​