as_date no longer supports argument "format"

[ian-price]

Between versions 1.6.0 and 1.7.1, the function as_date lost the ability to use the argument "format". I was using this when the date was embedded in part of the text.
the command

as_date(MY_INPUT, format = "MY_TEXT_%Y%m%d") 

returns an error in 1.7.1

Error in .local(x, ...) : unused argument (format = "MY_TEXT_%Y%m%d")

[vspinu]

Well, technically format argument was never part of the API, and it worked for character vectors because in 1.6.0 it did as.Date. In 1.7.0 a range of issues with character parsing were fixed (#598, #597, #536) and that means format argument can longer work. Sorry about that. You can use any of the available parser functions in lubridate - parse_date_time, parse_date_time2 or fast_strptime.

On your string, the simplest ymd(MY_INPUT) should work.

[ian-price]

Thanks for the quick response. For my needs, I replaced it with as.Date, so I'm fine. Thank you for the other suggestions.
I just wanted to report the change in functionality as I never know whether a change like this is intended or a side-effect. Sounds like it's intended, so I'll close the issue.

[vspinu]

as_date is advertised as drop-in replacement for as.Date. I will try to fix this.

[huftis]

Note that as_datetime() is also advertised as a drop-in replacement for as.POSIXct(), but doesn’t support the format argument, something as.POSIXct() does. But wouldn’t it be cleaner to have as_date() and as_datetime() not support the format argument (i.e. the current behaviour)? If people want to parse characters as dates or datetimes, they can easily use parse_date() and parse_datetime(), which does support a format argument, and which are drop-in replacements for as.Date() and as.POSIXct().

[vspinu]

parse_date and parse_datetime are not part of lubridate. In any case, parsers are not drop-ins for as.Date because they work on strings only.

I think, the best is to leave format argument to character methods as before. The issues is that lubridate parsers are not equivalent to strptime and one would need to treat this particular case specially and redirect it to strptime internally. This is how I plan to fix this at the moment.

[BastienFR]

The argument format should be remove from the help file if it's not used anymore. In my case, with lubridate_1.7.3, ?as_date gives a page with format. It's very confusing.

[vspinu]

It is supported.

[BastienFR]

Humm.... I feel bad now, it was a bug on my side, sending a numeric vector (for which format isn't supported, which makes sense) vs a character vector for which it is... my bad, sorry, I'm so used to work with date as characters...