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0 pointsnickpsecurity10y ago0 comments

Should be able to type or sanity check them like anything else. What specific issue are you worried about?

0 comments

henrikschroder10y ago

2011-02-28 + 1m1d = 2011-03-29

2011-02-28 + 1d1m = 2011-04-01

(edit: stupid leap-year!)

TimWolla10y ago

February 2012 has got 29 days.

henrikschroder10y ago

This is why everyone hates working with time and date functions. :-)

1 more reply

nickpsecurityOP10y ago

Why does that happen? I'd think they were equivalent. I don't do time-series or anything to be clear. I would just expect the a + b = b + a principle to apply for the m/d value.

32bitkid10y ago

because 1m = [28d,29d,30d,31d] depending on which month you are in. By adding 1d, pre or post, it can alter the definition of 1m.

2 more replies

henrikschroder10y ago

2011-02-28 + 1m1d = (2011-02-28 + 1m) + 1d = 2011-03-28 + 1d = 2011-03-29

2011-02-28 + 1d1m = (2011-02-28 + 1d) + 1m = 2011-03-01 + 1m = 2011-04-01

Also, you have these overflow rules:

2011-03-31 + 1m = 2011-04-30

2011-04-30 - 1m = 2011-03-30

j / k navigate · click thread line to collapse

0 comments

henrikschroder10y ago

2011-02-28 + 1m1d = 2011-03-29

2011-02-28 + 1d1m = 2011-04-01

(edit: stupid leap-year!)

TimWolla10y ago

February 2012 has got 29 days.

henrikschroder10y ago

This is why everyone hates working with time and date functions. :-)

1 more reply

nickpsecurityOP10y ago

Why does that happen? I'd think they were equivalent. I don't do time-series or anything to be clear. I would just expect the a + b = b + a principle to apply for the m/d value.

32bitkid10y ago

because 1m = [28d,29d,30d,31d] depending on which month you are in. By adding 1d, pre or post, it can alter the definition of 1m.

2 more replies

henrikschroder10y ago

2011-02-28 + 1m1d = (2011-02-28 + 1m) + 1d = 2011-03-28 + 1d = 2011-03-29

2011-02-28 + 1d1m = (2011-02-28 + 1d) + 1m = 2011-03-01 + 1m = 2011-04-01

Also, you have these overflow rules:

2011-03-31 + 1m = 2011-04-30

2011-04-30 - 1m = 2011-03-30

j / k navigate · click thread line to collapse