pyarrow.NativeFile¶

class pyarrow.NativeFile¶

Bases: pyarrow.lib._Weakrefable

The base class for all Arrow streams.

Streams are either readable, writable, or both. They optionally support seeking.

While this class exposes methods to read or write data from Python, the primary intent of using a Arrow stream is to pass it to other Arrow facilities that will make use of it, such as Arrow IPC routines.

Be aware that there are subtle differences with regular Python files, e.g. destroying a writable Arrow stream without closing it explicitly will not flush any pending data.

__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)
`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)¶

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.create_memory_map pyarrow.OSFile