35 — Diary: notes saved by date

A diary is one file per day. Python's datetime package tells you today's date, and the file helper from guide 13 saves and reads the note. Put the two together and every note lands in a file named after its day.

#Steps

1. Get today's date as text. date.today() from the datetime package (guide 24) knows the real date, and str() turns it into the text 2026-08-11:

   from datetime import date
   today = str(date.today())
   show today
   

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   The output is the real current date, so it shows today's date on any day.

2. Save a note into a file whose name contains the date. The f in f"..." fills {today} into the filename, then file_write and file_read from guide 13 store and load the note:

   use file latest
   from datetime import date
   today = str(date.today())
   file_write(f"diary-{today}.txt", "Had coffee with a friend.")
   show file_read(f"diary-{today}.txt")
   

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   A new file appears in the folder for each day the diary is used.

3. The whole diary is one menu loop, like the terminal menu from guide 22: add saves a note, read shows today or a past date, and quit breaks the loop. Save it as diary.nme:

   # A diary: each day's note goes to its own dated file.
   # Run: nme r diary
   
   use file latest
   from datetime import date
   
   show "diary menu (add, read, quit)"
   while True:
       ask action, "choice (add, read, quit): "
       if action == "add":
           ask note, "note: "
           today = str(date.today())
           file_write(f"diary-{today}.txt", note)
           show "saved to " + f"diary-{today}.txt"
       elif action == "read":
           ask when, "which day (today, date): "
           if when == "today":
               today = str(date.today())
               show file_read(f"diary-{today}.txt")
           else:
               ask day, "date (YYYY-MM-DD): "
               show file_read("diary-" + day + ".txt")
       else:
           show "bye"
           break
   

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4. Run it and feed the menu three answers — add a note, read today, quit:

   printf 'add\nHad coffee with a friend.\nread\ntoday\nquit\n' | nme r diary
   

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   diary menu (add, read, quit)
   choice (add, read, quit): note: saved to diary-2026-08-11.txt
   choice (add, read, quit): which day (today, date): Had coffee with a friend.
   choice (add, read, quit): bye
   

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   The filename shows the real date; yours prints today's date instead.

5. A past date is read the same way in reverse: ask collects the date and file_read opens that exact file. That is the read date branch:

   use file latest
   ask when, "which day (today, date): "
   if when == "today":
       today = str(date.today())
       show file_read(f"diary-{today}.txt")
   else:
       ask day, "date (YYYY-MM-DD): "
       show file_read("diary-" + day + ".txt")
   

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   The branch checks when, and only opens diary-<date>.txt when the day is not today.

#Try it yourself

Add a list choice that shows every diary file in the folder. from pathlib import Path and a for loop over Path(".").glob("diary-*.txt") lists the dated files:

from pathlib import Path
for p in sorted(Path(".").glob("diary-*.txt")):
    show p.name

Add list to the menu prompt and a new elif action == "list": branch that runs this loop.

#What you learned

• from datetime import date and str(date.today()) give today's date as text.
• f"diary-{today}.txt" builds a filename from the date.
• file_write saves a note to that file and file_read reads it back.
• A while True: menu turns one note per day into a growing diary.