Date Command Gives Wrong Week Number for Dec 31











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When I try to get the week number for Dec 31, it returns 1. When I get the week number for Dec 30, I get 52 --- which is what I would expect. The day Monday is correct. This is on a RPI running Ubuntu.



$ date -d "2018-12-30T1:58:55" +"%V%a"

52Sun

$ date -d "2018-12-31T1:58:55" +"%V%a"

01Mon


Same issue without time string



$ date -d "2018-12-31" +"%V%a"

01Mon









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  • 4




    "Date Command Gives Wrong Week Number for Dec 31" – "Wrong" according to which specification? Is the specification you are using the same one that the manual for date says it is using?
    – Jörg W Mittag
    16 hours ago






  • 2




    Excel week number inconsistent results, Excel weeknum function returns wrong week, UI calendar shows wrong week number
    – phuclv
    9 hours ago






  • 1




    You might be interested in Why does the MonthCalendar control show the wrong week numbers in Romania? The blog post is about Windows, but the issue being discussed is general (and seems to be the same as what you are encountering).
    – a CVn
    5 hours ago

















up vote
15
down vote

favorite












When I try to get the week number for Dec 31, it returns 1. When I get the week number for Dec 30, I get 52 --- which is what I would expect. The day Monday is correct. This is on a RPI running Ubuntu.



$ date -d "2018-12-30T1:58:55" +"%V%a"

52Sun

$ date -d "2018-12-31T1:58:55" +"%V%a"

01Mon


Same issue without time string



$ date -d "2018-12-31" +"%V%a"

01Mon









share|improve this question









New contributor




George Shafer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
















  • 4




    "Date Command Gives Wrong Week Number for Dec 31" – "Wrong" according to which specification? Is the specification you are using the same one that the manual for date says it is using?
    – Jörg W Mittag
    16 hours ago






  • 2




    Excel week number inconsistent results, Excel weeknum function returns wrong week, UI calendar shows wrong week number
    – phuclv
    9 hours ago






  • 1




    You might be interested in Why does the MonthCalendar control show the wrong week numbers in Romania? The blog post is about Windows, but the issue being discussed is general (and seems to be the same as what you are encountering).
    – a CVn
    5 hours ago















up vote
15
down vote

favorite









up vote
15
down vote

favorite











When I try to get the week number for Dec 31, it returns 1. When I get the week number for Dec 30, I get 52 --- which is what I would expect. The day Monday is correct. This is on a RPI running Ubuntu.



$ date -d "2018-12-30T1:58:55" +"%V%a"

52Sun

$ date -d "2018-12-31T1:58:55" +"%V%a"

01Mon


Same issue without time string



$ date -d "2018-12-31" +"%V%a"

01Mon









share|improve this question









New contributor




George Shafer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











When I try to get the week number for Dec 31, it returns 1. When I get the week number for Dec 30, I get 52 --- which is what I would expect. The day Monday is correct. This is on a RPI running Ubuntu.



$ date -d "2018-12-30T1:58:55" +"%V%a"

52Sun

$ date -d "2018-12-31T1:58:55" +"%V%a"

01Mon


Same issue without time string



$ date -d "2018-12-31" +"%V%a"

01Mon






linux command-line date






share|improve this question









New contributor




George Shafer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question









New contributor




George Shafer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|improve this question




share|improve this question








edited 19 hours ago









Jesse_b

11k22762




11k22762






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asked 19 hours ago









George Shafer

853




853




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New contributor





George Shafer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






George Shafer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.








  • 4




    "Date Command Gives Wrong Week Number for Dec 31" – "Wrong" according to which specification? Is the specification you are using the same one that the manual for date says it is using?
    – Jörg W Mittag
    16 hours ago






  • 2




    Excel week number inconsistent results, Excel weeknum function returns wrong week, UI calendar shows wrong week number
    – phuclv
    9 hours ago






  • 1




    You might be interested in Why does the MonthCalendar control show the wrong week numbers in Romania? The blog post is about Windows, but the issue being discussed is general (and seems to be the same as what you are encountering).
    – a CVn
    5 hours ago
















  • 4




    "Date Command Gives Wrong Week Number for Dec 31" – "Wrong" according to which specification? Is the specification you are using the same one that the manual for date says it is using?
    – Jörg W Mittag
    16 hours ago






  • 2




    Excel week number inconsistent results, Excel weeknum function returns wrong week, UI calendar shows wrong week number
    – phuclv
    9 hours ago






  • 1




    You might be interested in Why does the MonthCalendar control show the wrong week numbers in Romania? The blog post is about Windows, but the issue being discussed is general (and seems to be the same as what you are encountering).
    – a CVn
    5 hours ago










4




4




"Date Command Gives Wrong Week Number for Dec 31" – "Wrong" according to which specification? Is the specification you are using the same one that the manual for date says it is using?
– Jörg W Mittag
16 hours ago




"Date Command Gives Wrong Week Number for Dec 31" – "Wrong" according to which specification? Is the specification you are using the same one that the manual for date says it is using?
– Jörg W Mittag
16 hours ago




2




2




Excel week number inconsistent results, Excel weeknum function returns wrong week, UI calendar shows wrong week number
– phuclv
9 hours ago




Excel week number inconsistent results, Excel weeknum function returns wrong week, UI calendar shows wrong week number
– phuclv
9 hours ago




1




1




You might be interested in Why does the MonthCalendar control show the wrong week numbers in Romania? The blog post is about Windows, but the issue being discussed is general (and seems to be the same as what you are encountering).
– a CVn
5 hours ago






You might be interested in Why does the MonthCalendar control show the wrong week numbers in Romania? The blog post is about Windows, but the issue being discussed is general (and seems to be the same as what you are encountering).
– a CVn
5 hours ago












2 Answers
2






active

oldest

votes

















up vote
33
down vote













This is giving you the ISO week which starts on Monday's




The ISO week date system is effectively a leap week calendar system that is part of the ISO 8601 date and time standard issued by the International Organization for Standardization (ISO) since 1988 (last revised in 2004) and, before that, it was defined in ISO (R) 2015 since 1971. It is used (mainly) in government and business for fiscal years, as well as in timekeeping. This was previously known as "Industrial date coding". The system specifies a week year atop the Gregorian calendar by defining a notation for ordinal weeks of the year.








An ISO week-numbering year (also called ISO year informally) has 52 or 53 full weeks. That is 364 or 371 days instead of the usual 365 or 366 days. The extra week is sometimes referred to as a leap week, although ISO 8601 does not use this term.



Weeks start with Monday. Each week's year is the Gregorian year in which the Thursday falls. The first week of the year, hence, always contains 4 January. ISO week year numbering therefore slightly deviates from the Gregorian for some days close to 1 January.






If you want to show 12/31 as week 52 you should use %U which does not use the ISO standard:



$ date -d "2018-12-31T1:58:55" +"%V%a"
01Mon
$ date -d "2018-12-31T1:58:55" +"%U%a"
52Mon





share|improve this answer




























    up vote
    2
    down vote













    The definition of the week number is different between Europe and the USA, probably ISO versus ANSI standards. This may be related to a week being Sunday--Saturday or Monday--Sunday, and this again may be related to the Jewish versus Christian definition of the Lord's Day (Sabbath vs Sunday).



    For Europe, week number 1 contains the first Thursday in January, and thus it contains a minimum of 4 days (i.e. a majority) belonging to the new year (Thu-Fri-Sat-Sun).



    Anyway, in such years when ALL (!!) week numbers are +/- 1 different between Europe and the USA this gives great fun with setting schedules in multi-national companies. :-)






    share|improve this answer








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    StessenJ is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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      2 Answers
      2






      active

      oldest

      votes








      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes








      up vote
      33
      down vote













      This is giving you the ISO week which starts on Monday's




      The ISO week date system is effectively a leap week calendar system that is part of the ISO 8601 date and time standard issued by the International Organization for Standardization (ISO) since 1988 (last revised in 2004) and, before that, it was defined in ISO (R) 2015 since 1971. It is used (mainly) in government and business for fiscal years, as well as in timekeeping. This was previously known as "Industrial date coding". The system specifies a week year atop the Gregorian calendar by defining a notation for ordinal weeks of the year.








      An ISO week-numbering year (also called ISO year informally) has 52 or 53 full weeks. That is 364 or 371 days instead of the usual 365 or 366 days. The extra week is sometimes referred to as a leap week, although ISO 8601 does not use this term.



      Weeks start with Monday. Each week's year is the Gregorian year in which the Thursday falls. The first week of the year, hence, always contains 4 January. ISO week year numbering therefore slightly deviates from the Gregorian for some days close to 1 January.






      If you want to show 12/31 as week 52 you should use %U which does not use the ISO standard:



      $ date -d "2018-12-31T1:58:55" +"%V%a"
      01Mon
      $ date -d "2018-12-31T1:58:55" +"%U%a"
      52Mon





      share|improve this answer

























        up vote
        33
        down vote













        This is giving you the ISO week which starts on Monday's




        The ISO week date system is effectively a leap week calendar system that is part of the ISO 8601 date and time standard issued by the International Organization for Standardization (ISO) since 1988 (last revised in 2004) and, before that, it was defined in ISO (R) 2015 since 1971. It is used (mainly) in government and business for fiscal years, as well as in timekeeping. This was previously known as "Industrial date coding". The system specifies a week year atop the Gregorian calendar by defining a notation for ordinal weeks of the year.








        An ISO week-numbering year (also called ISO year informally) has 52 or 53 full weeks. That is 364 or 371 days instead of the usual 365 or 366 days. The extra week is sometimes referred to as a leap week, although ISO 8601 does not use this term.



        Weeks start with Monday. Each week's year is the Gregorian year in which the Thursday falls. The first week of the year, hence, always contains 4 January. ISO week year numbering therefore slightly deviates from the Gregorian for some days close to 1 January.






        If you want to show 12/31 as week 52 you should use %U which does not use the ISO standard:



        $ date -d "2018-12-31T1:58:55" +"%V%a"
        01Mon
        $ date -d "2018-12-31T1:58:55" +"%U%a"
        52Mon





        share|improve this answer























          up vote
          33
          down vote










          up vote
          33
          down vote









          This is giving you the ISO week which starts on Monday's




          The ISO week date system is effectively a leap week calendar system that is part of the ISO 8601 date and time standard issued by the International Organization for Standardization (ISO) since 1988 (last revised in 2004) and, before that, it was defined in ISO (R) 2015 since 1971. It is used (mainly) in government and business for fiscal years, as well as in timekeeping. This was previously known as "Industrial date coding". The system specifies a week year atop the Gregorian calendar by defining a notation for ordinal weeks of the year.








          An ISO week-numbering year (also called ISO year informally) has 52 or 53 full weeks. That is 364 or 371 days instead of the usual 365 or 366 days. The extra week is sometimes referred to as a leap week, although ISO 8601 does not use this term.



          Weeks start with Monday. Each week's year is the Gregorian year in which the Thursday falls. The first week of the year, hence, always contains 4 January. ISO week year numbering therefore slightly deviates from the Gregorian for some days close to 1 January.






          If you want to show 12/31 as week 52 you should use %U which does not use the ISO standard:



          $ date -d "2018-12-31T1:58:55" +"%V%a"
          01Mon
          $ date -d "2018-12-31T1:58:55" +"%U%a"
          52Mon





          share|improve this answer












          This is giving you the ISO week which starts on Monday's




          The ISO week date system is effectively a leap week calendar system that is part of the ISO 8601 date and time standard issued by the International Organization for Standardization (ISO) since 1988 (last revised in 2004) and, before that, it was defined in ISO (R) 2015 since 1971. It is used (mainly) in government and business for fiscal years, as well as in timekeeping. This was previously known as "Industrial date coding". The system specifies a week year atop the Gregorian calendar by defining a notation for ordinal weeks of the year.








          An ISO week-numbering year (also called ISO year informally) has 52 or 53 full weeks. That is 364 or 371 days instead of the usual 365 or 366 days. The extra week is sometimes referred to as a leap week, although ISO 8601 does not use this term.



          Weeks start with Monday. Each week's year is the Gregorian year in which the Thursday falls. The first week of the year, hence, always contains 4 January. ISO week year numbering therefore slightly deviates from the Gregorian for some days close to 1 January.






          If you want to show 12/31 as week 52 you should use %U which does not use the ISO standard:



          $ date -d "2018-12-31T1:58:55" +"%V%a"
          01Mon
          $ date -d "2018-12-31T1:58:55" +"%U%a"
          52Mon






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered 19 hours ago









          Jesse_b

          11k22762




          11k22762
























              up vote
              2
              down vote













              The definition of the week number is different between Europe and the USA, probably ISO versus ANSI standards. This may be related to a week being Sunday--Saturday or Monday--Sunday, and this again may be related to the Jewish versus Christian definition of the Lord's Day (Sabbath vs Sunday).



              For Europe, week number 1 contains the first Thursday in January, and thus it contains a minimum of 4 days (i.e. a majority) belonging to the new year (Thu-Fri-Sat-Sun).



              Anyway, in such years when ALL (!!) week numbers are +/- 1 different between Europe and the USA this gives great fun with setting schedules in multi-national companies. :-)






              share|improve this answer








              New contributor




              StessenJ is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
              Check out our Code of Conduct.






















                up vote
                2
                down vote













                The definition of the week number is different between Europe and the USA, probably ISO versus ANSI standards. This may be related to a week being Sunday--Saturday or Monday--Sunday, and this again may be related to the Jewish versus Christian definition of the Lord's Day (Sabbath vs Sunday).



                For Europe, week number 1 contains the first Thursday in January, and thus it contains a minimum of 4 days (i.e. a majority) belonging to the new year (Thu-Fri-Sat-Sun).



                Anyway, in such years when ALL (!!) week numbers are +/- 1 different between Europe and the USA this gives great fun with setting schedules in multi-national companies. :-)






                share|improve this answer








                New contributor




                StessenJ is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                Check out our Code of Conduct.




















                  up vote
                  2
                  down vote










                  up vote
                  2
                  down vote









                  The definition of the week number is different between Europe and the USA, probably ISO versus ANSI standards. This may be related to a week being Sunday--Saturday or Monday--Sunday, and this again may be related to the Jewish versus Christian definition of the Lord's Day (Sabbath vs Sunday).



                  For Europe, week number 1 contains the first Thursday in January, and thus it contains a minimum of 4 days (i.e. a majority) belonging to the new year (Thu-Fri-Sat-Sun).



                  Anyway, in such years when ALL (!!) week numbers are +/- 1 different between Europe and the USA this gives great fun with setting schedules in multi-national companies. :-)






                  share|improve this answer








                  New contributor




                  StessenJ is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                  Check out our Code of Conduct.









                  The definition of the week number is different between Europe and the USA, probably ISO versus ANSI standards. This may be related to a week being Sunday--Saturday or Monday--Sunday, and this again may be related to the Jewish versus Christian definition of the Lord's Day (Sabbath vs Sunday).



                  For Europe, week number 1 contains the first Thursday in January, and thus it contains a minimum of 4 days (i.e. a majority) belonging to the new year (Thu-Fri-Sat-Sun).



                  Anyway, in such years when ALL (!!) week numbers are +/- 1 different between Europe and the USA this gives great fun with setting schedules in multi-national companies. :-)







                  share|improve this answer








                  New contributor




                  StessenJ is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                  Check out our Code of Conduct.









                  share|improve this answer



                  share|improve this answer






                  New contributor




                  StessenJ is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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                  answered 3 hours ago









                  StessenJ

                  1211




                  1211




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                  New contributor





                  StessenJ is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                  Check out our Code of Conduct.






                  StessenJ is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                  Check out our Code of Conduct.






















                      George Shafer is a new contributor. Be nice, and check out our Code of Conduct.










                       

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