The as.date() function creates objects of the class “Date“, via input of character representations of dates.

Answers to the exercises are available here.

Exercise 1

The format of as.Date(x, ...) accepts character dates in the format, “YYYY-MM-DD”.

For the first exercise, use the c() function, and as.date(), to convert “2010-05-01” and “2004-03-15” to class “date” objects. Set a variable called, “Exer1Dates“.

Exercise 2

With as.Date(x, format, ...), the structure of the character dates are specified by the “format =” parameter.

For this exercise, use as.date(x, format, ...) to convert “07/19/98” to a date object within the variable, “Exer2Date“.

Exercise 3

The parameter, “origin =” converts dates from Windows Excel, (where 1900 is mistakenly designated as a leap year), to R format, via “origin = "1899-12-30"“.

Therefore, convert the Windows Excel dates of “31539“, “31540“, and
“31541” to date objects, without setting a variable.

Exercise 4

Convert “02/07/10“, “02/23/10“, “02/08/10“, “02/14/10“, and
“02/10/10“, into date objects within the variable, “Exer4Dates“.

Exercise 5

Find the mean of the date object variable “Exer4Dates“.

Exercise 6

Find the max date in “Exer4Dates“.

Exercise 7

Convert “10/25/2005“, and “06/08/1971” into a date object.

Exercise 8

Convert “Exer4Dates” to character data. Set a variable called, “chrDates“.

Exercise 9

Use the “format()“, and “Sys.Date()“, functions to print today’s date, with a format of “%B %d %Y“.

Exercise 10

Use “format()” and “Sys.time()” to print today’s date, with the time zone set to “Hawaii Standard Time“.

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