Over a million developers have joined DZone.
{{announcement.body}}
{{announcement.title}}

R: data.table/dplyr/lubridate - Error in wday

DZone's Guide to

R: data.table/dplyr/lubridate - Error in wday

· Big Data Zone
Free Resource

Learn best practices according to DataOps. Download the free O'Reilly eBook on building a modern Big Data platform.

Error in wday(date, label = TRUE, abbr = FALSE) : unused arguments (label = TRUE, abbr = FALSE)

I spent a couple of hours playing around with data.table this evening and tried changing some code written using a data frame to use a data table instead.

I started off by building a data frame which contains all the weekends between 2010 and 2015…

> library(lubridate)
 
> library(dplyr)
 
> dates = data.frame(date = seq( dmy("01-01-2010"), to=dmy("01-01-2015"), by="day" ))
 
> dates = dates %>% filter(wday(date, label = TRUE, abbr = FALSE) %in% c("Saturday", "Sunday"))

…which works fine:

> dates %>% head()
         date
1: 2010-01-02
2: 2010-01-03
3: 2010-01-09
4: 2010-01-10
5: 2010-01-16
6: 2010-01-17

I then tried to change the code to use a data table instead which led to the following error:

> library(data.table)
 
> dates = data.table(date = seq( dmy("01-01-2010"), to=dmy("01-01-2015"), by="day" ))
 
> dates = dates %>% filter(wday(date, label = TRUE, abbr = FALSE) %in% c("Saturday", "Sunday"))
Error in wday(date, label = TRUE, abbr = FALSE) : 
  unused arguments (label = TRUE, abbr = FALSE)

I wasn’t sure what was going on so I went back to the data frame version to check if that still worked…

> dates = data.frame(date = seq( dmy("01-01-2010"), to=dmy("01-01-2015"), by="day" ))
 
> dates = dates %>% filter(wday(date, label = TRUE, abbr = FALSE) %in% c("Saturday", "Sunday"))
Error in wday(c(1262304000, 1262390400, 1262476800, 1262563200, 1262649600,  : 
  unused arguments (label = TRUE, abbr = FALSE)

…except it now didn’t work either! I decided to check what wday was referring to…

Help on topic ‘wday’ was found in the following packages:

Integer based date class
(in package data.table in library /Library/Frameworks/R.framework/Versions/3.1/Resources/library)
Get/set days component of a date-time.
(in package lubridate in library /Library/Frameworks/R.framework/Versions/3.1/Resources/library)

…and realised that data.table has its own wday function – I’d been caught out by R’s global scoping of all the things!

We can probably work around that by the order in which we require the various libraries but for now I’m just prefixing the call to wday and all is well:

dates = dates %>% filter(lubridate::wday(date, label = TRUE, abbr = FALSE) %in% c("Saturday", "Sunday"))


Find the perfect platform for a scalable self-service model to manage Big Data workloads in the Cloud. Download the free O'Reilly eBook to learn more.

Topics:

Published at DZone with permission of Mark Needham, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}