pyarrow.FixedSizeBufferWriter¶

class pyarrow.FixedSizeBufferWriter¶

Bases: pyarrow.lib.NativeFile

A stream writing to a Arrow buffer.

__init__()¶: Initialize self. See help(type(self)) for accurate signature.

Methods

`__init__`()	Initialize self.
`close`(self)
`download`(self, stream_or_path[, buffer_size])	Read file completely to local path (rather than reading completely into memory).
`fileno`(self)	NOT IMPLEMENTED
`flush`(self)	Flush the stream, if applicable.
`isatty`(self)
`read`(self[, nbytes])	Read indicated number of bytes from file, or read all remaining bytes if no argument passed
`read1`(self[, nbytes])	Read and return up to n bytes.
`read_at`(self, nbytes, offset)	Read indicated number of bytes at offset from the file
`read_buffer`(self[, nbytes])
`readable`(self)
`readall`(self)
`readinto`(self, b)	Read into the supplied buffer
`readline`(self[, size])	NOT IMPLEMENTED.
`readlines`(self[, hint])	NOT IMPLEMENTED.
`seek`(self, int64_t position, int whence=0)	Change current file stream position
`seekable`(self)
`set_memcopy_blocksize`(self, int64_t blocksize)
`set_memcopy_threads`(self, int num_threads)
`set_memcopy_threshold`(self, int64_t threshold)
`size`(self)	Return file size
`tell`(self)	Return current stream position
`truncate`(self)	NOT IMPLEMENTED
`upload`(self, stream[, buffer_size])	Pipe file-like object to file
`writable`(self)
`write`(self, data)	Write byte from any object implementing buffer protocol (bytes, bytearray, ndarray, pyarrow.Buffer)
`writelines`(self, lines)

Attributes

`closed`
`mode`	The file mode.

close(self)¶

closed¶

download(self, stream_or_path, buffer_size=None)¶: Read file completely to local path (rather than reading completely into memory). First seeks to the beginning of the file.

fileno(self)¶: NOT IMPLEMENTED

flush(self)¶

Flush the stream, if applicable.

An error is raised if stream is not writable.

isatty(self)¶

mode¶

The file mode. Currently instances of NativeFile may support:

rb: binary read
wb: binary write
rb+: binary read and write

read(self, nbytes=None)¶

Read indicated number of bytes from file, or read all remaining bytes if no argument passed

Parameters: nbytes (int, default None) –
Returns: data (bytes)

read1(self, nbytes=None)¶

Read and return up to n bytes.

Alias for read, needed to match the IOBase interface.

read_at(self, nbytes, offset)¶

Read indicated number of bytes at offset from the file

Parameters

nbytes (int) –
offset (int) –

Returns

data (bytes)

read_buffer(self, nbytes=None)¶

readable(self)¶

readall(self)¶

readinto(self, b)¶

Read into the supplied buffer

Parameters: b (any python object supporting buffer interface) –
Returns: number of bytes written

readline(self, size=None)¶

NOT IMPLEMENTED. Read and return a line of bytes from the file.

If size is specified, read at most size bytes.

Line terminator is always b”n”.

readlines(self, hint=None)¶

NOT IMPLEMENTED. Read lines of the file

Parameters: hint (int maximum number of bytes read until we stop) –

seek(self, int64_t position, int whence=0)¶

Change current file stream position

Parameters

position (int) – Byte offset, interpreted relative to value of whence argument
whence (int, default 0) – Point of reference for seek offset

Notes

Values of whence: * 0 – start of stream (the default); offset should be zero or positive * 1 – current stream position; offset may be negative * 2 – end of stream; offset is usually negative

Returns: new_position (the new absolute stream position)

seekable(self)¶

set_memcopy_blocksize(self, int64_t blocksize)¶

set_memcopy_threads(self, int num_threads)¶

set_memcopy_threshold(self, int64_t threshold)¶

size(self)¶: Return file size

tell(self)¶: Return current stream position

truncate(self)¶: NOT IMPLEMENTED

upload(self, stream, buffer_size=None)¶: Pipe file-like object to file

writable(self)¶

write(self, data)¶

Write byte from any object implementing buffer protocol (bytes, bytearray, ndarray, pyarrow.Buffer)

Parameters: data (bytes-like object or exporter of buffer protocol) –
Returns: nbytes (number of bytes written)

writelines(self, lines)¶

pyarrow.BufferOutputStream pyarrow.MemoryMappedFile