dplyr - arrange () according to two criteria per group

Question

I have hourly weather collected for hundreds of farms for a period of five weeks before a sampling event. I want to determine the average Air_Temp for the three weeks prior to t

Answer 1

I am using ‘0.5.0.9001’ version of dplyr (pre-release of 0.6.0). The new version will be released soon.

for grouped df, the arrange will ignore grouping information by default:

## S3 method for class 'grouped_df'
arrange(.data, ..., .by_group = FALSE)

So you would have to manually set .by_group = TRUE in order to tell arrange that the df is grouped:

Weather1 <- Weather %>%
    group_by(File) %>%
    arrange(Date, Hour, .by_group = TRUE)