pyarrow.fs.SubTreeFileSystem#

classpyarrow.fs.SubTreeFileSystem(base_path,FileSystembase_fs)#

Bases:FileSystem

Delegates to another implementation after prepending a fixed base path.

This is useful to expose a logical view of a subtree of a filesystem,for example a directory in a LocalFileSystem.

Note, that this makes no security guarantee. For example, symlinks mayallow to “escape” the subtree and access other parts of the underlyingfilesystem.

Parameters:

base_pathstr

The root of the subtree.

base_fsFileSystem

FileSystem object the operations delegated to.

Examples

Create a LocalFileSystem instance:

>>>frompyarrowimportfs>>>local=fs.LocalFileSystem()>>>withlocal.open_output_stream('/tmp/local_fs.dat')asstream:...stream.write(b'data')4

Create a directory and a SubTreeFileSystem instance:

>>>local.create_dir('/tmp/sub_tree')>>>subtree=fs.SubTreeFileSystem('/tmp/sub_tree',local)

Write data into the existing file:

>>>withsubtree.open_append_stream('sub_tree_fs.dat')asf:...f.write(b'+newly added')12

Print out the attributes:

>>>subtree.base_fs<pyarrow._fs.LocalFileSystem object at ...>>>>subtree.base_path'/tmp/sub_tree/'

Get info for the given directory or given file:

>>>subtree.get_file_info('')<FileInfo for '': type=FileType.Directory>>>>subtree.get_file_info('sub_tree_fs.dat')<FileInfo for 'sub_tree_fs.dat': type=FileType.File, size=12>

Delete the file and directory:

>>>subtree.delete_file('sub_tree_fs.dat')>>>local.delete_dir('/tmp/sub_tree')>>>local.delete_file('/tmp/local_fs.dat')

For usage of the methods see examples forLocalFileSystem().

__init__(*args,**kwargs)#

Methods

__init__(*args, **kwargs)
copy_file(self, src, dest)	Copy a file.
create_dir(self, path, *, bool recursive=True)	Create a directory and subdirectories.
delete_dir(self, path)	Delete a directory and its contents, recursively.
delete_dir_contents(self, path, *, ...)	Delete a directory's contents, recursively.
delete_file(self, path)	Delete a file.
equals(self, FileSystem other)	Parameters:
from_uri(uri)	Create a new FileSystem from URI or Path.
get_file_info(self, paths_or_selector)	Get info for the given files.
move(self, src, dest)	Move / rename a file or directory.
normalize_path(self, path)	Normalize filesystem path.
open_append_stream(self, path[, ...])	Open an output stream for appending.
open_input_file(self, path)	Open an input file for random access reading.
open_input_stream(self, path[, compression, ...])	Open an input stream for sequential reading.
open_output_stream(self, path[, ...])	Open an output stream for sequential writing.

Attributes

base_fs
base_path
type_name	The filesystem's type name.

base_fs#

base_path#

copy_file(self,src,dest)#

Copy a file.

If the destination exists and is a directory, an error is returned.Otherwise, it is replaced.

Parameters:

srcstr

The path of the file to be copied from.

deststr

The destination path where the file is copied to.

Examples

>>>local.copy_file(path,...local_path+'/pyarrow-fs-example_copy.dat')

Inspect the file info:

>>>local.get_file_info(local_path+'/pyarrow-fs-example_copy.dat')<FileInfo for '/.../pyarrow-fs-example_copy.dat': type=FileType.File, size=4>>>>local.get_file_info(path)<FileInfo for '/.../pyarrow-fs-example.dat': type=FileType.File, size=4>

create_dir(self,path,*,boolrecursive=True)#

Create a directory and subdirectories.

This function succeeds if the directory already exists.

Parameters:

pathstr

The path of the new directory.

recursivebool, defaultTrue

Create nested directories as well.

delete_dir(self,path)#

Delete a directory and its contents, recursively.

Parameters:

pathstr

The path of the directory to be deleted.

delete_dir_contents(self,path,*,boolaccept_root_dir=False,boolmissing_dir_ok=False)#

Delete a directory’s contents, recursively.

Like delete_dir, but doesn’t delete the directory itself.

Parameters:

pathstr

The path of the directory to be deleted.

accept_root_dirbool, defaultFalse

Allow deleting the root directory’s contents(if path is empty or “/”)

missing_dir_okbool, defaultFalse

If False then an error is raised if path doesnot exist

delete_file(self,path)#

Delete a file.

Parameters:

pathstr

The path of the file to be deleted.

equals(self,FileSystemother)#

Parameters:

otherpyarrow.fs.FileSystem

Returns:

bool

staticfrom_uri(uri)#

Create a new FileSystem from URI or Path.

Recognized URI schemes are “file”, “mock”, “s3fs”, “gs”, “gcs”, “hdfs” and “viewfs”.In addition, the argument can be a pathlib.Path object, or a stringdescribing an absolute local path.

Parameters:

uristr

URI-based path, for example:file:///some/local/path.

Returns:

tuple of (FileSystem,str path)

With (filesystem, path) tuple where path is the abstract pathinside the FileSystem instance.

Examples

Create a new FileSystem subclass from a URI:

>>>uri='file:///{}/pyarrow-fs-example.dat'.format(local_path)>>>local_new,path_new=fs.FileSystem.from_uri(uri)>>>local_new<pyarrow._fs.LocalFileSystem object at ...>>>path_new'/.../pyarrow-fs-example.dat'

Or from a s3 bucket:

>>>fs.FileSystem.from_uri("s3://usgs-landsat/collection02/")(<pyarrow._s3fs.S3FileSystem object at ...>, 'usgs-landsat/collection02')

get_file_info(self,paths_or_selector)#

Get info for the given files.

Any symlink is automatically dereferenced, recursively. A non-existingor unreachable file returns a FileStat object and has a FileType ofvalue NotFound. An exception indicates a truly exceptional condition(low-level I/O error, etc.).

Parameters:

paths_or_selectorFileSelector, path-like orlist of path-likes

Either a selector object, a path-like object or a list ofpath-like objects. The selector’s base directory will not bepart of the results, even if it exists. If it doesn’t exist,useallow_not_found.

Returns:

FileInfo orlist ofFileInfo

Single FileInfo object is returned for a single path, otherwisea list of FileInfo objects is returned.

Examples

>>>local<pyarrow._fs.LocalFileSystem object at ...>>>>local.get_file_info("/{}/pyarrow-fs-example.dat".format(local_path))<FileInfo for '/.../pyarrow-fs-example.dat': type=FileType.File, size=4>

move(self,src,dest)#

Move / rename a file or directory.

If the destination exists:- if it is a non-empty directory, an error is returned- otherwise, if it has the same type as the source, it is replaced- otherwise, behavior is unspecified (implementation-dependent).

Parameters:

srcstr

The path of the file or the directory to be moved.

deststr

The destination path where the file or directory is moved to.

Examples

Create a new folder with a file:

>>>local.create_dir('/tmp/other_dir')>>>local.copy_file(path,'/tmp/move_example.dat')

Move the file:

>>>local.move('/tmp/move_example.dat',...'/tmp/other_dir/move_example_2.dat')

Inspect the file info:

>>>local.get_file_info('/tmp/other_dir/move_example_2.dat')<FileInfo for '/tmp/other_dir/move_example_2.dat': type=FileType.File, size=4>>>>local.get_file_info('/tmp/move_example.dat')<FileInfo for '/tmp/move_example.dat': type=FileType.NotFound>

Delete the folder:>>> local.delete_dir(‘/tmp/other_dir’)

normalize_path(self,path)#

Normalize filesystem path.

Parameters:

pathstr

The path to normalize

Returns:

normalized_pathstr

The normalized path

open_append_stream(self,path,compression='detect',buffer_size=None,metadata=None)#

Open an output stream for appending.

If the target doesn’t exist, a new empty file is created.

Note

Some filesystem implementations do not support efficientappending to an existing file, in which case this method willraise NotImplementedError.Consider writing to multiple files (using e.g. the dataset layer)instead.

Parameters:

pathstr

The source to open for writing.

compressionstr optional, default ‘detect’

The compression algorithm to use for on-the-fly compression.If “detect” and source is a file path, then compression will bechosen based on the file extension.If None, no compression will be applied. Otherwise, a well-knownalgorithm name must be supplied (e.g. “gzip”).

buffer_sizeint optional, defaultNone

If None or 0, no buffering will happen. Otherwise the size of thetemporary write buffer.

metadatadict optional, defaultNone

If not None, a mapping of string keys to string values.Some filesystems support storing metadata along the file(such as “Content-Type”).Unsupported metadata keys will be ignored.

Returns:

streamNativeFile

Examples

Append new data to a FileSystem subclass with nonempty file:

>>>withlocal.open_append_stream(path)asf:...f.write(b'+newly added')12

Print out the content to the file:

>>>withlocal.open_input_file(path)asf:...print(f.readall())b'data+newly added'

open_input_file(self,path)#

Open an input file for random access reading.

Parameters:

pathstr

The source to open for reading.

Returns:

streamNativeFile

Examples

Print the data from the file withopen_input_file():

>>>withlocal.open_input_file(path)asf:...print(f.readall())b'data'

open_input_stream(self,path,compression='detect',buffer_size=None)#

Open an input stream for sequential reading.

Parameters:

pathstr

The source to open for reading.

compressionstr optional, default ‘detect’

The compression algorithm to use for on-the-fly decompression.If “detect” and source is a file path, then compression will bechosen based on the file extension.If None, no compression will be applied. Otherwise, a well-knownalgorithm name must be supplied (e.g. “gzip”).

buffer_sizeint optional, defaultNone

If None or 0, no buffering will happen. Otherwise the size of thetemporary read buffer.

Returns:

streamNativeFile

Examples

Print the data from the file withopen_input_stream():

>>>withlocal.open_input_stream(path)asf:...print(f.readall())b'data'

open_output_stream(self,path,compression='detect',buffer_size=None,metadata=None)#

Open an output stream for sequential writing.

If the target already exists, existing data is truncated.

Parameters:

pathstr

The source to open for writing.

compressionstr optional, default ‘detect’

The compression algorithm to use for on-the-fly compression.If “detect” and source is a file path, then compression will bechosen based on the file extension.If None, no compression will be applied. Otherwise, a well-knownalgorithm name must be supplied (e.g. “gzip”).

buffer_sizeint optional, defaultNone

If None or 0, no buffering will happen. Otherwise the size of thetemporary write buffer.

metadatadict optional, defaultNone

If not None, a mapping of string keys to string values.Some filesystems support storing metadata along the file(such as “Content-Type”).Unsupported metadata keys will be ignored.

Returns:

streamNativeFile

Examples

>>>local=fs.LocalFileSystem()>>>withlocal.open_output_stream(path)asstream:...stream.write(b'data')4

type_name#

The filesystem’s type name.