I am using dplyr 0.1.1 on R 3.0.2 on MacOS Mavericks.
What you see below crashes on the 'group_by' command, either that I converted the SCHEDULED_OFF column to a full timestamp or to date only, as in the example.
df <- read.csv(pipe("unzip -p myfile.zip"), header = TRUE, colClasses = "character")
df <- df[, c("SPORTS_ID", "SCHEDULED_OFF", "VOLUME_MATCHED")]
df <- df[!is.na(df$SCHEDULED_OFF),]
df$SCHEDULED_OFF <- strptime(df$SCHEDULED_OFF, "%d-%m-%Y")
class(df$SCHEDULED_OFF)
[1] "POSIXlt" "POSIXt"
df2 <- group_by(df, SCHEDULED_OFF)
The input dataset is > 600k rows. I am sorry I am not authorised to share it
Giacecco