How to get week number in Python

Question

How to find out what week number is current year on June 16th  wk24  with Python

User · Answer

I believe date isocalendar   is going to be the answer  This article explains the math behind ISO 8601 Calendar  Check out the date isocalendar   portion of the datetime page of the Python documentation    gt  gt  gt  dt   datetime date 2010  6  16    gt  gt  gt  wk   dt isocalendar   1  24    isocalendar   return a 3-tuple with  year  wk num  wk day   dt isocalendar   0  returns the year dt isocalendar   1  returns the week number  dt isocalendar   2  returns the week day  Simple as can be

User · Answer

For the integer value of the instantaneous week of the year try   import datetime datetime datetime utcnow   isocalendar   1

User · Answer

You can try  W directive as below   d   datetime datetime strptime  2016-06-16    Y- m- d   print datetime datetime strftime d   W        W   Week number of the year  Monday as the first day of the week  as a decimal number  All days in a new year preceding the first Monday are considered to be in week 0   00  01       53

User · Answer

There are many systems for week numbering  The following are the most common systems simply put with code examples    ISO  First week starts with Monday and must contain the January 4th  The ISO calendar is already implemented in Python    gt  gt  gt  from datetime import date  gt  gt  gt  date 2014  12  29  isocalendar    2   2015  1   North American  First week starts with Sunday and must contain the January 1st  The following code is my modified version of Python s ISO calendar implementation for the North American system   from datetime import date  def week from date date object       date ordinal   date object toordinal       year   date object year     week     date ordinal -  week1 start ordinal year      7    1     if week  gt   52          if date ordinal  gt    week1 start ordinal year   1               year    1             week   1     return year  week  def  week1 start ordinal year       jan1   date year  1  1      jan1 ordinal   jan1 toordinal       jan1 weekday   jan1 weekday       week1 start ordinal   jan1 ordinal -   jan1 weekday   1    7      return week1 start ordinal    gt  gt  gt  from datetime import date  gt  gt  gt  week from date date 2014  12  29    2015  1   MMWR  CDC   First week starts with Sunday and must contain the January 4th  I created the epiweeks package specifically for this numbering system  also has support for the ISO system   Here is an example    gt  gt  gt  from datetime import date  gt  gt  gt  from epiweeks import Week  gt  gt  gt  Week fromdate date 2014  12  29    2014  53

User · Answer

isocalendar   returns incorrect year and weeknumber values for some dates   Python 2 7 3  default  Feb 27 2014  19 58 35    GCC 4 6 3  on linux2 Type  help    copyright    credits  or  license  for more information   gt  gt  gt  import datetime as dt  gt  gt  gt  myDateTime   dt datetime strptime  20141229T000000 000Z    Y m dT H M S  fZ    gt  gt  gt  yr weekNumber weekDay   myDateTime isocalendar    gt  gt  gt  print  Year is     str yr       weekNumber is     str weekNumber  Year is 2015  weekNumber is 1   Compare with Mark Ransom s approach    gt  gt  gt  yr   myDateTime year  gt  gt  gt  weekNumber     myDateTime - dt datetime yr 1 1   days 7    1  gt  gt  gt  print  Year is     str yr       weekNumber is     str weekNumber  Year is 2014  weekNumber is 52

User · Answer

datetime date has a isocalendar   method  which returns a tuple containing the calendar week    gt  gt  gt  import datetime  gt  gt  gt  datetime date 2010  6  16  isocalendar   1  24   datetime date isocalendar   is an instance-method returning a tuple containing year  weeknumber and weekday in respective order for the given date instance

User · Answer

A lot of answers have been given  but id like to add to them   If you need the week to display as a year week style  ex  1953 - week 53 of 2019  2001 - week 1 of 2020 etc    you can do this   import datetime  year   datetime datetime now   week num   datetime date year year  year month  year day  strftime   V   long week num   str year year  0 2    str week num    It will take the current year and week  and long week num in the day of writing this will be    gt  gt  gt  2006

User · Answer

The ISO week suggested by others is a good one  but it might not fit your needs  It assumes each week begins with a Monday  which leads to some interesting anomalies at the beginning and end of the year   If you d rather use a definition that says week 1 is always January 1 through January 7  regardless of the day of the week  use a derivation like this    gt  gt  gt  testdate datetime datetime 2010 6 16   gt  gt  gt  print   testdate - datetime datetime testdate year 1 1   days    7    1  24

User · Answer

Here s another option  import time from time import gmtime  strftime d   time strptime  quot 16 Jun 2010 quot    quot  d  b  Y quot   print strftime d    U     which prints 24  See  http   docs python org library datetime html strftime-and-strptime-behavior

User · Answer

I summarize the discussion to two steps   Convert the raw format to a datetime object  Use the function of a datetime object or a date object to calculate the week number   Warm up from datetime import datetime  date  time d   date 2005  7  14  t   time 12  30  dt   datetime combine d  t  print dt   1st step To manually generate a datetime object  we can use datetime datetime 2017 5 3  or datetime datetime now    But in reality  we usually need to parse an existing string  we can use strptime function  such as datetime strptime  2017-5-3    Y- m- d   in which you have to specific the format  Detail of different format code can be found in the official documentation  Alternatively  a more convenient way is to use dateparse module  Examples are dateparser parse  16 Jun 2010    dateparser parse  12 2 12   or dateparser parse  2017-5-3   The above two approaches will return a datetime object  2nd step Use the obtained  datetime object to call strptime format   For example  python dt   datetime strptime  2017-01-1    Y- m- d     return a datetime object  This day is Sunday print dt strftime  quot  W quot       00  Monday as the 1st day of the week  All days in a new year preceding the 1st Monday are considered to be in week 0  print dt strftime  quot  U quot       01  Sunday as the 1st day of the week  All days in a new year preceding the 1st Sunday are considered to be in week 0  print dt strftime  quot  V quot       52  Monday as the 1st day of the week  Week 01 is the week containing Jan 4   It s very tricky to decide which format to use  A better way is to get a date object to call isocalendar    For example  python dt   datetime strptime  2017-01-1    Y- m- d     return a datetime object d   dt date     convert to a date object  equivalent to d   date 2017 1 1   but date strptime   don t have the parse function year  week  weekday   d isocalendar    print year  week  weekday     2016 52 7  in the ISO standard  In reality  you will be more likely to use date isocalendar    to prepare a weekly report  especially in the Christmas-New Year shopping season

User · Answer

Generally to get the current week number  starts from Sunday    from datetime import   today   datetime today   print today strftime   U

User · Answer

If you are only using the isocalendar week number across the board the following should be sufficient   import datetime week   date year 2014  month 1  day 1  isocalendar   1    This retrieves the second member of the tuple returned by isocalendar for our week number   However  if you are going to be using date functions that deal in the Gregorian calendar  isocalendar alone will not work   Take the following example   import datetime date   datetime datetime strptime  2014-1-1     Y- W- w   week   date isocalendar   1    The string here says to return the Monday of the first week in 2014 as our date   When we use isocalendar to retrieve the week number here  we would expect to get the same week number back  but we don t   Instead we get a week number of 2   Why   Week 1 in the Gregorian calendar is the first week containing a Monday   Week 1 in the isocalendar is the first week containing a Thursday   The partial week at the beginning of 2014 contains a Thursday  so this is week 1 by the isocalendar  and making date week 2   If we want to get the Gregorian week  we will need to convert from the isocalendar to the Gregorian   Here is a simple function that does the trick   import datetime  def gregorian week date         The isocalendar week for this date     iso week   date isocalendar   1         The baseline Gregorian date for the beginning of our date s year     base greg   datetime datetime strptime   d-1-1    date year    Y- W- w          If the isocalendar week for this date is not 1  we need to        decrement the iso week by 1 to get the Gregorian week number     return iso week if base greg isocalendar   1     1 else iso week - 1

User · Answer

userInput   input   Please enter project deadline date  dd mm yyyy        import datetime  currentDate   datetime datetime today    testVar   datetime datetime strptime userInput    d  b  Y   date    remainDays   testVar - currentDate date    remainWeeks    remainDays days   7 0    1   print   Please pay attention for deadline of project X in days and weeks are        remainDays     and    remainWeeks     Weeks   nSo  hurryup

User · Answer

You can get the week number directly from datetime as string    gt  gt  gt  import datetime  gt  gt  gt  datetime date 2010  6  16  strftime   V    24    Also you can get different  types  of the week number of the year changing the strftime parameter for       U - Week number of the year  Sunday as the first day of the week  as a zero padded decimal number  All days in a new year preceding the first Sunday are considered to be in week 0  Examples  00  01       53       W - Week number of the year  Monday as the first day of the week  as a decimal number  All days in a new year preceding the first Monday are considered to be in week 0  Examples  00  01       53                  Added in Python 3 6  backported to some distribution s Python 2 7 s  Several additional directives not required by the C89 standard are included for convenience  These parameters all correspond to ISO 8601 date values  These may not be available on all platforms when used with the strftime   method                    V - ISO 8601 week as a decimal number with Monday as the first day of the week  Week 01 is the week containing Jan 4   Examples  01  02       53      from  datetime  mdash  Basic date and time types  mdash  Python 3 7 3 documentation   I ve found out about it from here  It worked for me in Python 2 7 6

[python] How to get week number in Python?

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