The following matches a calendar month, e.g., 2008-08. The hyphen is
required:
^([0-9]{4})-(1[0-2]|0[1-9])$| Regex options:
None |
| Regex flavors: .NET,
Java, JavaScript, PCRE, Perl, Python, Ruby |
^(?<year>[0-9]{4})-(?<month>1[0-2]|0[1-9])$| Regex options:
None |
| Regex flavors: .NET,
PCRE 7, Perl 5.10, Ruby 1.9 |
^(?P<year>[0-9]{4})-(?P<month>1[0-2]|0[1-9])$| Regex options:
None |
| Regex flavors: PCRE,
Python |
Calendar date, e.g., 2008-08-30. The hyphens are optional.
This regex allows YYYY-MMDD and YYYYMM-DD, which do not follow ISO
8601:
^([0-9]{4})-?(1[0-2]|0[1-9])-?(3[0-1]|0[1-9]|[1-2][0-9])$| Regex options:
None |
| Regex flavors: .NET,
Java, JavaScript, PCRE, Perl, Python, Ruby |
^(?<year>[0-9]{4})-?(?<month>1[0-2]|0[1-9])-?↵
(?<day>3[0-1]|0[1-9]|[1-2][0-9])$| Regex options:
None |
| Regex flavors: .NET,
PCRE 7, Perl 5.10, Ruby 1.9 |
Calendar date, e.g., 2008-08-30. The hyphens are optional.
This regex uses a conditional to exclude YYYY-MMDD and YYYYMM-DD.
There is an extra capturing group for the first hyphen:
^([0-9]{4})(-)?(1[0-2]|0[1-9])(?(2)-)(3[0-1]|0[1-9]|[1-2][0-9])$| Regex options:
None |
| Regex flavors: .NET,
PCRE, Perl, Python |
Calendar date, e.g., 2008-08-30. The hyphens are optional.
This regex uses alternation to exclude YYYY-MMDD and YYYYMM-DD. There
are two capturing groups for the month:
^([0-9]{4})(?:(1[0-2]|0[1-9])|-?(1[0-2]|0[1-9])-?)↵
(3[0-1]|0[1-9]|[1-2][0-9])$| Regex options:
None |
| Regex flavors: .NET,
Java, JavaScript, PCRE, Perl, Python, Ruby |
Week of the year, e.g., 2008-W35. The hyphen is
optional:
^([0-9]{4})-?W(5[0-3]|[1-4][0-9]|0[1-9])$| Regex options:
None |
| Regex flavors: .NET,
Java, JavaScript, PCRE, Perl, Python, Ruby |
^(?<year>[0-9]{4})-?W(?<week>5[0-3]|[1-4][0-9]|0[1-9])$| Regex options:
None |
| Regex flavors: .NET,
PCRE 7, Perl 5.10, Ruby 1.9 |
Week date, e.g., 2008-W35-6. The hyphens are
optional:
^([0-9]{4})-?W(5[0-3]|[1-4][0-9]|0[1-9])-?([1-7])$| Regex options:
None |
| Regex flavors: .NET,
Java, JavaScript, PCRE, Perl, Python, Ruby |
^(?<year>[0-9]{4})-?W(?<week>5[0-3]|[1-4][0-9]|0[1-9])-?(?<day>[1-7])$| Regex options:
None |
| Regex flavors: .NET,
PCRE 7, Perl 5.10, Ruby 1.9 |
Ordinal date, e.g., 2008-243. The hyphen is
optional:
^([0-9]{4})-?(36[0-6]|3[0-5][0-9]|[12][0-9]{2}|0[1-9][0-9]|00[1-9])$| Regex options:
None |
| Regex flavors: .NET,
Java, JavaScript, PCRE, Perl, Python, Ruby |
^(?<year>[0-9]{4})-?↵
(?<day>36[0-6]|3[0-5][0-9]|[12][0-9]{2}|0[1-9][0-9]|00[1-9])$| Regex options:
None |
| Regex flavors: .NET,
PCRE 7, Perl 5.10, Ruby 1.9 |
Hours and minutes, e.g., 17:21. The colon is optional:
^(2[0-3]|[01]?[0-9]):?([0-5]?[0-9])$
| Regex options:
None |
| Regex flavors: .NET,
Java, JavaScript, PCRE, Perl, Python, Ruby |
^(?<hour>2[0-3]|[01]?[0-9]):?(?<minute>[0-5]?[0-9])$
| Regex options:
None |
| Regex flavors: .NET,
PCRE 7, Perl 5.10, Ruby 1.9 |
Hours, minutes, and seconds, e.g., 17:21:59. The colons are
optional:
^(2[0-3]|[01]?[0-9]):?([0-5]?[0-9]):?([0-5]?[0-9])$
| Regex options:
None |
| Regex flavors: .NET,
Java, JavaScript, PCRE, Perl, Python, Ruby |
^(?<hour>2[0-3]|[01]?[0-9]):?(?<minute>[0-5]?[0-9]):?↵
(?<second>[0-5]?[0-9])$
| Regex options:
None |
| Regex flavors: .NET,
PCRE 7, Perl 5.10, Ruby 1.9 |
Time zone designator, e.g., Z, +07 or +07:00. The colons and the minutes are
optional:
^(Z|[+-](?:2[0-3]|[01]?[0-9])(?::?(?:[0-5]?[0-9]))?)$
| Regex options:
None |
| Regex flavors: .NET,
Java, JavaScript, PCRE, Perl, Python, Ruby |
Hours, minutes, and seconds with time zone designator, e.g.,
17:21:59+07:00. All the colons are
optional. The minutes in the time zone designator are also
optional:
^(2[0-3]|[01]?[0-9]):?([0-5]?[0-9]):?([0-5]?[0-9])↵
(Z|[+-](?:2[0-3]|[01]?[0-9])(?::?(?:[0-5]?[0-9]))?)$
| Regex options:
None |
| Regex flavors: .NET,
Java, JavaScript, PCRE, Perl, Python, Ruby |
^(?<hour>2[0-3]|[01]?[0-9]):?(?<minute>[0-5]?[0-9]):?(?<sec>[0-5]?[0-9])↵
(?<timezone>Z|[+-](?:2[0-3]|[01]?[0-9])(?::?(?:[0-5]?[0-9]))?)$
| Regex options:
None |
| Regex flavors: .NET,
PCRE 7, Perl 5.10, Ruby 1.9 |
Date, with optional time zone, e.g., 2008-08-30 or 2008-08-30+07:00.
Hyphens are required. This is the XML Schema date type:
^(-?(?:[1-9][0-9]*)?[0-9]{4})-(1[0-2]|0[1-9])-(3[0-1]|0[1-9]|[1-2][0-9])↵
(Z|[+-](?:2[0-3]|[0-1][0-9]):[0-5][0-9])?$| Regex options:
None |
| Regex flavors: .NET,
Java, JavaScript, PCRE, Perl, Python, Ruby |
^(?<year>-?(?:[1-9][0-9]*)?[0-9]{4})-(?<month>1[0-2]|0[1-9])-↵
(?<day>3[0-1]|0[1-9]|[1-2][0-9])↵
(?<timezone>Z|[+-](?:2[0-3]|[0-1][0-9]):[0-5][0-9])?$| Regex options:
None |
| Regex flavors: .NET,
PCRE 7, Perl 5.10, Ruby 1.9 |
Time, with optional microseconds and time zone, e.g., 01:45:36 or 01:45:36.123+07:00.
This is the XML Schema dateTime type:
^(2[0-3]|[0-1][0-9]):([0-5][0-9]):([0-5][0-9])(\.[0-9]+)?↵
(Z|[+-](?:2[0-3]|[0-1][0-9]):[0-5][0-9])?$
| Regex options:
None |
| Regex flavors: .NET,
Java, JavaScript, PCRE, Perl, Python, Ruby |
^(?<hour>2[0-3]|[0-1][0-9]):(?<minute>[0-5][0-9]):(?<second>[0-5][0-9])↵
(?<ms>\.[0-9]+)?(?<timezone>Z|[+-](?:2[0-3]|[0-1][0-9]):[0-5][0-9])?$
| Regex options:
None |
| Regex flavors: .NET,
PCRE 7, Perl 5.10, Ruby 1.9 |
Date and time, with optional microseconds and time zone, e.g.,
2008-08-30T01:45:36 or 2008-08-30T01:45:36.123Z. This is the
XML Schema dateTime
type:
^(-?(?:[1-9][0-9]*)?[0-9]{4})-(1[0-2]|0[1-9])-(3[0-1]|0[1-9]|[1-2][0-9])↵
T(2[0-3]|[0-1][0-9]):([0-5][0-9]):([0-5][0-9])(\.[0-9]+)?↵
(Z|[+-](?:2[0-3]|[0-1][0-9]):[0-5][0-9])?$| Regex options:
None |
| Regex flavors: .NET,
Java, JavaScript, PCRE, Perl, Python, Ruby |
^(?<year>-?(?:[1-9][0-9]*)?[0-9]{4})-(?<month>1[0-2]|0[1-9])-↵
(?<day>3[0-1]|0[1-9]|[1-2][0-9])T(?<hour>2[0-3]|[0-1][0-9]):↵
(?<minute>[0-5][0-9]):(?<second>[0-5][0-9])(?<ms>\.[0-9]+)?↵
(?<timezone>Z|[+-](?:2[0-3]|[0-1][0-9]):[0-5][0-9])?$| Regex options:
None |
| Regex flavors: .NET,
PCRE 7, Perl 5.10, Ruby 1.9 |
ISO 8601 defines a wide range of date and time formats. The
regular expressions presented here cover the most common formats, but
most systems that use ISO 8601 use only a subset. For example, in XML
Schema dates and times, the hyphens and colons are mandatory. To make
hyphens and colons mandatory, simply remove the question marks after
them. To disallow hyphens and colons, remove the hyphens and colons
along with the question mark that follows them. Do watch out for the
noncapturing groups, which use the ‹(?:group)› syntax. If a question mark and a
colon follow an opening parenthesis, those three characters open a
noncapturing group.
The regular expressions make the individual hyphens and colons
optional, which does not follow ISO 8601 exactly. For example,
1733:26 is
not a valid ISO 8601 time, but will be accepted by the time regexes.
Requiring all hyphens and colons to be present or omitted at the same
time makes your regex quite a bit more complex. We’ve done this as an
example for the date regex, but in practice, as with the XML Schema
types, the delimiters are usually required or disallowed rather than
optional.
We put parentheses around all the number parts of the regex.
That makes it easy to retrieve the numbers for the years, months,
days, hours, minutes, seconds, and time zones. Recipe 2.9 explains how parentheses create capturing
groups. Recipe 3.9 explains how you
can retrieve the text matched by those capturing groups in procedural
code.
For most regexes, we also show an alternative using named
capture. Some of these date and time formats may be unfamiliar to you
or your fellow developers. Named capture makes the regex easier to
understand. .NET, PCRE 7, Perl 5.10, and Ruby 1.9 support the ‹(?<name>group)› syntax.
All versions of PCRE and Python covered in this book support the
alternative ‹(?P<name>group)› syntax, which adds a
‹P›. See Recipe 2.11 and Recipe 3.9 for details.
The number ranges in all the regexes are strict. For example,
the calendar day is restricted between 01 and 31. You’ll never end up
with day 32 or month 13. None of the regexes here attempt to exclude
invalid day and month combinations, such as February 31st; Recipe 4.5 explains how you can deal with
that.
Though some of these regexes are quite long, they’re all very
straightforward and use the same techniques explained in Recipe 4.4 and Recipe 4.6.
