Refactors quarter() API to allow for quarter start- and end-dates

[tomcardoso]

Addresses #947. With this, the API now looks like:

quarter(x) # default behaviour is unchanged
quarter(x, type = "quarter_year") # equivalent to what would previously be passing `with_year = TRUE`
quarter(x, type = "date_first") # new functionality
quarter(x, type = "date_last") # new functionality

The with_year parameter is soft-deprecated, but will continue to work for the time being.

[tomcardoso]

One thing: I tried running pkgdown::build_site() but got an error about tidytemplate not being installed. Is rebuilding docs something that happens separately from the PR?

[DavisVaughan]

FWIW these capabilities come built into the upcoming clock package, where the year-quarter-day calendar is a first class type.

library(clock)
library(lubridate)

x <- as.Date("2019-04-25")

yqd1 <- as_year_quarter_day(x)
yqd1
#> <year_quarter_day<January><day>[1]>
#> [1] "2019-Q2-25"

# Get the quarter
quarter(x)
#> [1] 2
get_quarter(yqd1)
#> [1] 2

# Change the fiscal start month and try again
yqd2 <- as_year_quarter_day(x, start = clock_months$april)
yqd2
#> <year_quarter_day<April><day>[1]>
#> [1] "2020-Q1-25"

quarter(x, fiscal_start = 4)
#> [1] 1
get_quarter(yqd2)
#> [1] 1

# Get the year+quarter
quarter(x, type = "quarter_year")
#> [1] 2019.2
paste0(get_year(yqd1), ".", get_quarter(yqd1))
#> [1] "2019.2"

# or, more appropriately:
calendar_narrow(yqd1, "quarter")
#> <year_quarter_day<January><quarter>[1]>
#> [1] "2019-Q2"

# Get the first day of the quarter
quarter(x, type = "date_first")
#> [1] "2019-04-01"
as.Date(set_day(yqd1, 1))
#> [1] "2019-04-01"

# Get the last day of the quarter
quarter(x, type = "date_last")
#> [1] "2019-06-30"
as.Date(set_day(yqd1, "last"))
#> [1] "2019-06-30"

^{Created on 2021-03-03 by the reprex package (v1.0.0)}

[tomcardoso]

@DavisVaughan Neat! Is the idea that clock would supersede lubridate eventually, since it's coming from the r-lib folks?

[DavisVaughan]

Not really supersede. Instead we currently are thinking of it as an alternative to lubridate, with lubridate still living on and being a powerful tool for working with date-times. In the far future, bits and pieces of lubridate (like this, for example) might end up relying on clock, but that is still a little uncertain.

[tomcardoso]

Hey @vspinu, any thoughts on this? Let me know if you want me to tweak anything.

[vspinu]

Sorry for delaying on this. There was an issue with the logical check which could fail for non-logical inputs. Also I don't quite like quarter_year because the return values is actually of the form year.quarter. So I have renamed that type. Please see my amendments. If it's ok with you I will merge.

[vspinu]

@tomcardoso you might have missed my last message. If you disagree with my amendments please let me know.

[tomcardoso]

Oh shoot, sorry @vspinu, I did miss this. Makes total sense to me – thanks for talking me through this stuff. Looking forward to putting the new functionality to use!