12: Working with Dates and Times

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How would you put the 1AD 2nd of January 1am 2 minutes and 3 seconds in ISO 8601 format? (the kind of ISO 8601 R likes)

0001-01-02 01:02:03

How do you create a date object and POSIXct object?

Use the as.Date() and as.POSIXct function

What package and function converts data in many forms into a Date or POSIXct?

anytime

What is the easiest function to use to determine the latest Date in a vector of Dates?

max()

When parsing a frequently used date or datetime order, what lubridate function should you use?

lubridate should have specialized functions for most of these orders

What lubridate function makes a date? What function makes a datetime? What feature makes these functions useful?

make_date()

make_datetime()

These functions are useful because they can take vectors as arguments, which allows for entries from datasets

What lubridate function extracts the year from a date? What is another use for this function?

year()

This function can be used to duplicate a date and then change its year

For the month function, how do you get the months to display as strings instead of numerics?

label = TRUE

What function take a boolean vector, and returns TRUE if one of the datavalues is TRUE?

any()

What are the rounding functions for dates and datetimes? What units can you round to?

floor_date()

ceiling_date ()

round_date()

Any units, including amounts of units (e.g. 5 minutes)

What function gives you the difference between dates?

difftime()

Which lubridate function gives you the current datetime?

now()

What is the difference between periods and durations in lubridate?

Periods are measured in standard timekeeping terms, while durations are measured in seconds

How would you add a period of a day and a duration of a day to a date named x?

x + day(1)

x + dday(1)

How would you create a sequence of periods or durations?

x:x * period(x)

What operators add or subtract months in a manner that fixes overflow? (ex: Jan 31st + 1 month = February NA)

%m+%

%m-%

What operator tells you if a date is within a certain period?

%within%

What function extracts a timezone from a date or datetime?

tz()

What function creates a clone of a time or datetime with the same time but a different time zone?

force_tz()

What function creates a clone of a time or datetime but in a different time zone with the time translated over?

with_tz()

What function returns a list of all timezones?

OlsonNames()

What package revolves around times without dates?

hms

What package parses dates and datetimes quickly?

fasttime

What lubridate function parses dates or datetimes quickly?

fast_strptime

What lubridate function creates a function that formats a date or datetime in your manner of choosing?

stamp()

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