Add the data filename as a column

This function only exists insidearrowdplyr queries, and it only isvalid when querying on aFileSystemDataset.

Usage

add_filename()

Value

AFieldRefExpression that refers to the filenameaugmented column.

Details

To use filenames generated by this function in subsequent pipeline steps, youmust either callcompute() orcollect() first. See Examples.

Examples

if(FALSE){# \dontrun{open_dataset("nyc-taxi")|>mutate(  file=add_filename())# To use a verb like mutate() with add_filename() we need to first call# compute()open_dataset("nyc-taxi")|>mutate(file=add_filename())|>compute()|>mutate(filename_length=nchar(file))}# }