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Java's SimpleDateFormat: YYYY vs. Yyyy

• ghkbrew 2y ago
  Why does YYYY exist? Is there some common need I'm not familiar with? Also, I clicked on the title because I wanted to know what format Yyyy was... I feel mislead.
  • masklinn 2y ago
    The article is truly worthless for not explaining it. YYYY is for ISO week-years e.g. December 30, 2024 was also W01 2025 in the ISO calendar. Similarly January 1st 2027 will be W53 2026. ISO weeks are in common use in Europe.
    • skissane 2y ago
      This API would have been so much less error-prone if it had used symbolic names instead - e.g. “{year}”, “{weekYear}”, maybe even something like “{year:2}” for a 2 digit year.
      • masklinn 2y ago
        Good or bad, it’s the Unicode locale formatting langage (LDML).
  • IsTom 2y ago
    > Why does YYYY exist? In some countries (EU?) things get counted towards tax years based on it. It's probably useful for accounting software.
  • singlow 2y ago
    In case no one else noticed, Yyyy is not real. Its caused by automatic capitalization of yyyy in the HN title.
• voidUpdate 2y ago
  (2019)
• deleted 2y ago
  [deleted]
• brettgriffin 2y ago
  A lot of analytical and financial reporting has to tie activity to its ISO week, often to roll that activity up to the correct month and year. YYYY is perfect for that.
• mcculley 2y ago
  The title case formatting in the headline is making this more confusing than it should be (Yyyy should be yyyy).