Regular Expression to validate a timestamp

Question

I need a regular expression to validate a timestamp of the format, using Javascript:

YYYY/MM/DD HH:MI:SS

I trie

Answer 1

Here is a regex I wrote earlier today for validating strings in a format similar to what you mentioned: YYYY-MM-DD hh:mm:ss. It does not identify some bad dates (for example, February 30th) but may be slightly better than using the simplistic \d at each position. Things to note:

1. you can specify just a date, just a time, or both date + time
2. time can be in 12-hour or 24-hour format
3. seconds are optional

4. am/pm is optional

   const std::string dateAndTimeRegex =
       "^\\s*"                     // ignore whitespace
       "("                         // start of date
           "20[123][0-9]"          // year: 2010, 2011, ..., through 2039
           "\\W"                   // delimiter between year and month; typically will be "-"
           "([0]?[0-9]|1[012])"    // month: 0 through 9, or 00 through 09, or 10 through 12
           "\\W"                   // delimiter between month and day; typically will be "-"
           "([012]?[0-9]|3[01])"   // day: 0 through 9, or 00 through 29, or 30, or 31
       ")?"                        // end of optional date
       "\\s?"                      // optional whitespace
       "("                         // start of time
           "([01]?[0-9]|2[0-3])"   // hour: 0 through 9, or 00 through 19, or 20 through 23
           "\\W"                   // delimiter between hours and minutes; typically will be ":"
           "([0-5][0-9])"          // minute: 00 through 59
           "("                     // start of seconds (optional)
               "\\W"               // delimiter between minutes and seconds; typically will be ":"
               "([0-5][0-9])"      // seconds: 00 through 59
           ")?"                    // end of optional seconds
           "(\\s*[AaPp][Mm])?"     // optional AM, am, PM, pm
       ")?"                        // end of optional time
       "\\s*$";                    // trailing whitespace
   

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A comment from @kyrias hints that this regex will fail in a few months once we hit the year 2020. Depending on how you use it, you'll need to change "201[0-9]" to something else.

For example, if you are looking to validate the current date +/- a few years, you could change it to "20[12][0-9]". To validate 2000 through 2099, change it to "20[0-9]{2}".

I've changed the original regex above to look for 2010-2039. Someone else can edit this answer in 20 years if necessary.