Shoutbox

quote:

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Originally posted by haydn
I would use option B. I count "one year" as 365 days. If you add 365 calendar days to February 29 2004 you end up with March the first, 2005.

Contradictory to this however, if it were 29-2-04 and somebody was to ask me "What are you doing in one year and one day from now?" I would probably assume they were talking about March 1st, 2005.

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And that last one is indeed exactly what this poll is about.... You as the viewer do not know which target date is meant. You need to determine that by simply seeing "1 year and 0 days" or "1 year and 1 days". How it is calculated is the problem for the programmer

So let me ask it differently:

If the current date is 29-2-04, and you see in someones nickname: "in 1 year and 1 day the earth will end", on what day will the earth end, as your gut feeling would say it?

quote:

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Originally posted by haydn
My final 'gut' answer is option B, but only in the case where it is going from one leap year to the next 'non-leap' year.

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but that isn't an answer to the question though. the startdate and time remaining is especially choosen for this delimma, it wouldn't work with another.

(btw: it doesn't matter which method you pick if you go from one leap year to another, it will always be "x years and 0 days" (even with method A) for whatever starting date)

quote:

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Originally posted by haydn
Note: Does the title suggest there are going to be other dilemmas?

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Possible... highly depends on the thoughts and views replied in this thread

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keep those detailed views and thoughts comming guys, they are very usefull and important...

quote:

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Originally posted by John Anderton
Btw cookie, its Febuary not februari

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Wrong, it's February

quote:

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Originally posted by haydn
Contradictory to this however, if it were 29-2-04 and somebody was to ask me "What are you doing in one year and one day from now?" I would probably assume they were talking about March 1st, 2005.

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I agree with that.

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Originally posted by WDZ
To me, it makes more sense for the larger units to be added first (years > days) so I chose option B.

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That's the way I think too, but then Feb29 + 1 year = Feb29, so you'd need to add another day so answer A. Now, doesn't that make perfect sense?

Basically, adding a year does not change the date, it changes the year. So to change the date you would also have to add that one day as well. Like if you'd add a month to February 15th you'd end up on March 15th - still the 15th, just another month. The same goes for July 15th to August 15th. Now, there's a different amount of days between Feb15 and March15 than between Jul15 and Aug15, but that doesn't matter - that's rather irrelevant. So if we use the same reasons here, it's answer A you get.

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Originally posted by Tochjo
Basically, adding a year does not change the date, it changes the year. So to change the date you would also have to add that one day as well. Like if you'd add a month to February 15th you'd end up on March 15th - still the 15th, just another month. The same goes for July 15th to August 15th. Now, there's a different amount of days between Feb15 and March15 than between Jul15 and Aug15, but that doesn't matter - that's rather irrelevant. So if we use the same reasons here, it's answer A you get.

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But what if you are on March 31st and i say you that we can have dinner in a months time when ill be back (staying with cookies dinner theme )
Then according to your analogy i would be comming back on the 31st of april which does not exist. Your idea sticks to the fact that as long as you are incrementing a date by a constant number, and the date you end up on exists, its ok.
But what if after incrementing from date 'A' to date 'B' you find that date 'B' doesnt exist (April 31st or Feb 29 on a non leap year like 2005/2006)
In the latter case (which is currently under consideration) by default you need to increment the date by 'unity' so as to reach a date which exists.

Dont tell me that if you were leaving on the 31st of march and coming back on the 1st of Jan May you would say that ill be back in precisely 1 month and 1 day
You will return in 1 month and 0 days.

The time period "one month" (in lamens terms whilst talking) is considered to be the time from the current date till the same date in a month.

Thus, whilst speaking time between 15th feb - 15th march = 15th march - 15th april = 1 month

Thats why i think its B

quote:

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Originally posted by John Anderton
Dont tell me that if you were leaving on the 31st of march and coming back on the 1st of Janmay you would say that ill be back in precisely 1 month and 1 day
You will return in 1 month and 0 days.

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Is that really so? What if you left on april 1st... wouldn't that be "1 month and 0 days" to come to the date 'may 1st'?

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Originally posted by CookieRevised

quote:

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Originally posted by John Anderton
Dont tell me that if you were leaving on the 31st of march and coming back on the 1st of Janmay you would say that ill be back in precisely 1 month and 1 day
You will return in 1 month and 0 days.

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Is that really so? What if you left on april 1st... wouldn't that be "1 month and 0 days" to come to the date 'may 1st'?

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You cant consider a day back to be the rounded off day ??

Like if you are on march 31st and you have to go 1 month ahead then you "ideally" land up on 31st april which doesnt exist.
So you have 2 possibilities. You can either go with 30th of April or with 1st of may

Well that basically is your dillema isnt it. Jumping from an existing date to a non existant one leads to the need of rounding up of the date (either incrementing or decrementing)

If we decrement it we get 'x' years 'y' months and 1 day.
If we increment it we get 'x' years 'y' months and 0 days.

So my solution is that we increment it based on the simple principle of rounding up of decimals so to speak. Even tho we dont cosider the time in hours to round up, i would rather increment it cause thats what most of us do.

Today ill go and post this question to my friends as well. Ill pm you with the results so you can add them to the poll

I see you need this for that Holiday countdown plugin

I've done a lot of additional research regarding this and the thing I've found is that all sources regarding this subject avoid this kind of calculation. Even the ISO standards avoid this.

There is no real clear definition of how one should calculate or deal with this kind of date differences. If differences between dates are calculated it is never done in "years" or "months".

Nevertheless, in the updated Holiday Counter Plugin I've used method B as described in this thread (and seemingly prefered by most, not always for the good reasons but still...). Method A is available as well, as also two analytical methods where months and years have a fixed amount of days.