Menu
I am looking to add and subtract six months (bond time) reliably with lubridate.
For example, adding six months to 12/31/2014 should result in 6/30/2015, and adding to 2/28/2014 should result in 8/31/2014
The issue with as.Date("2014-12-31") + months(6), is that it yields an NA. Alternatively, the second result is 8/28/2014 because it doesn't just add 6 months to the month and then know where the day should end up dependent upon the month.
Is there any way to quickly correct this? At the moment, I am building a function to basically use a switch and consider each month, but this is very long and I am having problems with it as well.
Thanks!
659
You can use the EDATE function to quickly add or subtract months from a date. The EDATE function requires two arguments: the start date and the number of months that you want to add or subtract. To subtract months, enter a negative number as the second argument. For example, =EDATE("9/15/19",-5) returns 4/15/19.
Subtract months from a date in Python using PandasPandas provide a class DateOffset, to store the duration or interval information. It is mostly used to increment or decrement a timestamp. It can be used with datetime module to to subtract N months from a date.
The easiest way to subtract months from a date in Python is to use the dateutil extension. The relativedelta object from the dateutil. relativedelta module allows you to subtract any number of months from a date object.
The lubridate function %m+% may be useful here:
Add and subtract months to a date without exceeding the last day of the new month
as.Date("2014-12-31") %m+% months(6) # [1] "2015-06-30" To also handle the second case, you will need to round up to nearest month using ceiling_date, and subtract one day using days.
ceiling_date(as.Date("2014-02-28") %m+% months(6), unit = "month") - days(1) # [1] "2014-08-31" If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
