Convert to from DateTime and Time in Ruby

Question

How do you convert between a DateTime and a Time object in Ruby

User · Answer

Unfortunately  the DateTime to time  Time to datetime and Time parse functions don t retain the timezone info  Everything is converted to local timezone during conversion  Date arithmetics still work but you won t be able to display the dates with their original timezones  That context information is often important  For example  if I want to see transactions performed during business hours in New York I probably prefer to see them displayed in their original timezones  not my local timezone in Australia  which 12 hrs ahead of New York    The conversion methods below do keep that tz info   For Ruby 1 8  look at Gordon Wilson s answer  It s from the good old reliable Ruby Cookbook   For Ruby 1 9  it s slightly easier   require  date     Create a date in some foreign time zone  middle of the Atlantic  d   DateTime new 2010 01 01  10 00 00  Rational -2  24   puts d    Convert DateTime to Time  keeping the original timezone t   Time new d year  d month  d day  d hour  d min  d sec  d zone  puts t    Convert Time to DateTime  keeping the original timezone d   DateTime new t year  t month  t day  t hour  t min  t sec  Rational t gmt offset   3600  24   puts d   This prints the following  2010-01-01T10 00 00-02 00 2010-01-01 10 00 00 -0200 2010-01-01T10 00 00-02 00   The full original DateTime info including timezone is kept

User · Answer

Improving on Gordon Wilson solution  here is my try   def to time    Convert a fraction of a day to a number of microseconds   usec    sec fraction   60   60   24    10  6   to i   t   Time gm year  month  day  hour  min  sec  usec    t - offset abs div SECONDS IN DAY  end   You ll get the same time in UTC  loosing the timezone  unfortunately   Also  if you have ruby 1 9  just try the to time method

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require  time  require  date   t   Time now d   DateTime now  dd   DateTime parse t to s  tt   Time parse d to s

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Improving on Gordon Wilson solution  here is my try   def to time    Convert a fraction of a day to a number of microseconds   usec    sec fraction   60   60   24    10  6   to i   t   Time gm year  month  day  hour  min  sec  usec    t - offset abs div SECONDS IN DAY  end   You ll get the same time in UTC  loosing the timezone  unfortunately   Also  if you have ruby 1 9  just try the to time method

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As an update to the state of the Ruby ecosystem  Date  DateTime and Time now have methods to convert between the various classes  Using Ruby 1 9 2    pry  1  pry main  gt  ts    Jan 1  2000 12 01 01    gt   Jan 1  2000 12 01 01   2  pry main  gt  require  time    gt  true  3  pry main  gt  require  date    gt  true  4  pry main  gt  ds   Date parse ts    gt    lt Date  2000-01-01  4903089 2 0 2299161  gt   5  pry main  gt  ds to date   gt    lt Date  2000-01-01  4903089 2 0 2299161  gt   6  pry main  gt  ds to datetime   gt    lt DateTime  2000-01-01T00 00 00 00 00  4903089 2 0 2299161  gt   7  pry main  gt  ds to time   gt  2000-01-01 00 00 00 -0700  8  pry main  gt  ds to time class   gt  Time  9  pry main  gt  ds to datetime class   gt  DateTime  10  pry main  gt  ts   Time parse ts    gt  2000-01-01 12 01 01 -0700  11  pry main  gt  ts class   gt  Time  12  pry main  gt  ts to date   gt    lt Date  2000-01-01  4903089 2 0 2299161  gt   13  pry main  gt  ts to date class   gt  Date  14  pry main  gt  ts to datetime   gt    lt DateTime  2000-01-01T12 01 01-07 00  211813513261 86400 -7 24 2299161  gt   15  pry main  gt  ts to datetime class   gt  DateTime

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As an update to the state of the Ruby ecosystem  Date  DateTime and Time now have methods to convert between the various classes  Using Ruby 1 9 2    pry  1  pry main  gt  ts    Jan 1  2000 12 01 01    gt   Jan 1  2000 12 01 01   2  pry main  gt  require  time    gt  true  3  pry main  gt  require  date    gt  true  4  pry main  gt  ds   Date parse ts    gt    lt Date  2000-01-01  4903089 2 0 2299161  gt   5  pry main  gt  ds to date   gt    lt Date  2000-01-01  4903089 2 0 2299161  gt   6  pry main  gt  ds to datetime   gt    lt DateTime  2000-01-01T00 00 00 00 00  4903089 2 0 2299161  gt   7  pry main  gt  ds to time   gt  2000-01-01 00 00 00 -0700  8  pry main  gt  ds to time class   gt  Time  9  pry main  gt  ds to datetime class   gt  DateTime  10  pry main  gt  ts   Time parse ts    gt  2000-01-01 12 01 01 -0700  11  pry main  gt  ts class   gt  Time  12  pry main  gt  ts to date   gt    lt Date  2000-01-01  4903089 2 0 2299161  gt   13  pry main  gt  ts to date class   gt  Date  14  pry main  gt  ts to datetime   gt    lt DateTime  2000-01-01T12 01 01-07 00  211813513261 86400 -7 24 2299161  gt   15  pry main  gt  ts to datetime class   gt  DateTime

User · Answer

require  time  require  date   t   Time now d   DateTime now  dd   DateTime parse t to s  tt   Time parse d to s

User · Answer

You ll need two slightly different conversions   To convert from  Time  to  DateTime you can amend the Time class as follows   require  date  class Time   def to datetime       Convert seconds   microseconds into a fractional number of seconds     seconds   sec   Rational usec  10  6         Convert a UTC offset measured in minutes to one measured in a       fraction of a day      offset   Rational utc offset  60   60   24      DateTime new year  month  day  hour  min  seconds  offset    end end   Similar adjustments to Date will let you convert  DateTime  to  Time    class Date   def to gm time     to time new offset   gm    end    def to local time     to time new offset DateTime now offset-offset    local    end    private   def to time dest  method       Convert a fraction of a day to a number of microseconds     usec    dest sec fraction   60   60   24    10  6   to i     Time send method  dest year  dest month  dest day  dest hour  dest min                dest sec  usec    end end   Note that you have to choose between local time and GM UTC time   Both the above code snippets are taken from O Reilly s Ruby Cookbook  Their code reuse policy permits this

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While making such conversions one should take into consideration the behavior of timezones while converting from one object to the other  I found some good notes and examples in this stackoverflow post

User · Answer

While making such conversions one should take into consideration the behavior of timezones while converting from one object to the other  I found some good notes and examples in this stackoverflow post

User · Answer

You ll need two slightly different conversions   To convert from  Time  to  DateTime you can amend the Time class as follows   require  date  class Time   def to datetime       Convert seconds   microseconds into a fractional number of seconds     seconds   sec   Rational usec  10  6         Convert a UTC offset measured in minutes to one measured in a       fraction of a day      offset   Rational utc offset  60   60   24      DateTime new year  month  day  hour  min  seconds  offset    end end   Similar adjustments to Date will let you convert  DateTime  to  Time    class Date   def to gm time     to time new offset   gm    end    def to local time     to time new offset DateTime now offset-offset    local    end    private   def to time dest  method       Convert a fraction of a day to a number of microseconds     usec    dest sec fraction   60   60   24    10  6   to i     Time send method  dest year  dest month  dest day  dest hour  dest min                dest sec  usec    end end   Note that you have to choose between local time and GM UTC time   Both the above code snippets are taken from O Reilly s Ruby Cookbook  Their code reuse policy permits this

User · Answer

require  time  require  date   t   Time now d   DateTime now  dd   DateTime parse t to s  tt   Time parse d to s

User · Answer

require  time  require  date   t   Time now d   DateTime now  dd   DateTime parse t to s  tt   Time parse d to s

User · Answer

You can use to date  e g   gt  Event last starts at   gt  Wed  13 Jan 2021 16 49 36 292979000 CET  01 00  gt  Event last starts at to date   gt  Wed  13 Jan 2021

User · Answer

You ll need two slightly different conversions   To convert from  Time  to  DateTime you can amend the Time class as follows   require  date  class Time   def to datetime       Convert seconds   microseconds into a fractional number of seconds     seconds   sec   Rational usec  10  6         Convert a UTC offset measured in minutes to one measured in a       fraction of a day      offset   Rational utc offset  60   60   24      DateTime new year  month  day  hour  min  seconds  offset    end end   Similar adjustments to Date will let you convert  DateTime  to  Time    class Date   def to gm time     to time new offset   gm    end    def to local time     to time new offset DateTime now offset-offset    local    end    private   def to time dest  method       Convert a fraction of a day to a number of microseconds     usec    dest sec fraction   60   60   24    10  6   to i     Time send method  dest year  dest month  dest day  dest hour  dest min                dest sec  usec    end end   Note that you have to choose between local time and GM UTC time   Both the above code snippets are taken from O Reilly s Ruby Cookbook  Their code reuse policy permits this

User · Answer

You can use to date  e g   gt  Event last starts at   gt  Wed  13 Jan 2021 16 49 36 292979000 CET  01 00  gt  Event last starts at to date   gt  Wed  13 Jan 2021

User · Answer

You ll need two slightly different conversions   To convert from  Time  to  DateTime you can amend the Time class as follows   require  date  class Time   def to datetime       Convert seconds   microseconds into a fractional number of seconds     seconds   sec   Rational usec  10  6         Convert a UTC offset measured in minutes to one measured in a       fraction of a day      offset   Rational utc offset  60   60   24      DateTime new year  month  day  hour  min  seconds  offset    end end   Similar adjustments to Date will let you convert  DateTime  to  Time    class Date   def to gm time     to time new offset   gm    end    def to local time     to time new offset DateTime now offset-offset    local    end    private   def to time dest  method       Convert a fraction of a day to a number of microseconds     usec    dest sec fraction   60   60   24    10  6   to i     Time send method  dest year  dest month  dest day  dest hour  dest min                dest sec  usec    end end   Note that you have to choose between local time and GM UTC time   Both the above code snippets are taken from O Reilly s Ruby Cookbook  Their code reuse policy permits this

User · Answer

Unfortunately  the DateTime to time  Time to datetime and Time parse functions don t retain the timezone info  Everything is converted to local timezone during conversion  Date arithmetics still work but you won t be able to display the dates with their original timezones  That context information is often important  For example  if I want to see transactions performed during business hours in New York I probably prefer to see them displayed in their original timezones  not my local timezone in Australia  which 12 hrs ahead of New York    The conversion methods below do keep that tz info   For Ruby 1 8  look at Gordon Wilson s answer  It s from the good old reliable Ruby Cookbook   For Ruby 1 9  it s slightly easier   require  date     Create a date in some foreign time zone  middle of the Atlantic  d   DateTime new 2010 01 01  10 00 00  Rational -2  24   puts d    Convert DateTime to Time  keeping the original timezone t   Time new d year  d month  d day  d hour  d min  d sec  d zone  puts t    Convert Time to DateTime  keeping the original timezone d   DateTime new t year  t month  t day  t hour  t min  t sec  Rational t gmt offset   3600  24   puts d   This prints the following  2010-01-01T10 00 00-02 00 2010-01-01 10 00 00 -0200 2010-01-01T10 00 00-02 00   The full original DateTime info including timezone is kept

[ruby] Convert to/from DateTime and Time in Ruby

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