RecordBatchWriter {arrow}R Documentation

RecordBatchWriter classes


Apache Arrow defines two formats for serializing data for interprocess communication (IPC): a "stream" format and a "file" format, known as Feather. RecordBatchStreamWriter and RecordBatchFileWriter are interfaces for writing record batches to those formats, respectively.

For guidance on how to use these classes, see the examples section.


The RecordBatchFileWriter$create() and RecordBatchStreamWriter$create() factory methods instantiate the object and take the following arguments:


See Also

write_ipc_stream() and write_feather() provide a much simpler interface for writing data to these formats and are sufficient for many use cases. write_to_raw() is a version that serializes data to a buffer.


tf <- tempfile()

batch <- record_batch(chickwts)

# This opens a connection to the file in Arrow
file_obj <- FileOutputStream$create(tf)
# Pass that to a RecordBatchWriter to write data conforming to a schema
writer <- RecordBatchFileWriter$create(file_obj, batch$schema)
# You may write additional batches to the stream, provided that they have
# the same schema.
# Call "close" on the writer to indicate end-of-file/stream
# Then, close the connection--closing the IPC message does not close the file

# Now, we have a file we can read from. Same pattern: open file connection,
# then pass it to a RecordBatchReader
read_file_obj <- ReadableFile$create(tf)
reader <- RecordBatchFileReader$create(read_file_obj)
# RecordBatchFileReader knows how many batches it has (StreamReader does not)
# We could consume the Reader by calling $read_next_batch() until all are,
# consumed, or we can call $read_table() to pull them all into a Table
tab <- reader$read_table()
# Call to turn that Table into an R data.frame
df <-
# This should be the same data we sent
all.equal(df, chickwts, check.attributes = FALSE)
# Unlike the Writers, we don't have to close RecordBatchReaders,
# but we do still need to close the file connection

[Package arrow version 4.0.1 Index]