The disk.frame group by operation perform group WITHIN each chunk. This is often used for performance reasons. If the user wishes to perform group-by, they may choose to use the hard_group_by function which is expensive as it reorganizes the chunks by the shard key.

# S3 method for disk.frame
group_by(.data, ...)

chunk_group_by(.data, ...)

## Arguments

.data a disk.frame same as the dplyr::group_by