libpysal.io.fileio.FileIO

class libpysal.io.fileio.FileIO(dataPath='', mode='r', dataFormat=None)

Metaclass for supporting spatial data file read and write.

How this works:

FileIO.open(\*args) == FileIO(\*args)

When creating a new instance of FileIO the .__new__ method intercepts. .__new__ parses the filename to determine the fileType. Next, .__registry and checked for that type. Each type supports one or more modes (['r', 'w', 'a', etc.]). If we support the type and mode, an instance of the appropriate handler is created and returned. All handlers must inherit from this class, and by doing so are automatically added to the .__registry and are forced to conform to the prescribed API. The metaclass takes care of the registration by parsing the class definition. It doesn’t make much sense to treat weights in the same way as shapefiles and dbfs, so…

• … for now we’ll just return an instance of W on mode='r'.

• … on mode='w', .write will expect an instance of W.

__init__(dataPath='', mode='r', dataFormat=None)

Methods

__init__([dataPath, mode, dataFormat])
cast(key, typ)	Cast key as typ.
check()	Prints the contents of the registry.
close()	Subclasses should clean themselves up and then call this method.
flush()
get(n)	Seeks the file to n and returns n.
getType(dataPath, mode[, dataFormat])	Parse the dataPath and return the data type.
open(*args, **kwargs)	Alias for FileIO().
read([n])	Read at most n objects, less if read hits EOF.
seek(n)	Seek the FileObj to the beginning of the n'th record.
tell()	Return ID (or offset) of next object.
truncate([size])	Should be implemented by subclasses and redefine this doc string.
write(obj)	Must be implemented by subclasses that support 'w' subclasses Should increment .pos.

Attributes

by_row
ids
rIds

property by_row

cast(key, typ)

Cast key as typ.

Raises:

TypeError

Raised when a cast object in not callable.

KeyError

Raised when a key is not present.

classmethod check()

Prints the contents of the registry.

close()

Subclasses should clean themselves up and then call this method.

flush()

Raises:

NotImplementedError

get(n: int) → list

Seeks the file to n and returns n. If .ids is set n should be an id, else, n should be an offset.

static getType(dataPath: str, mode: str, dataFormat=None) → str

Parse the dataPath and return the data type.

property ids

classmethod open(*args, **kwargs)

Alias for FileIO().

property rIds: dict | None

read(n=-1) → list | None

Read at most n objects, less if read hits EOF. If size is negative or omitted read all objects until EOF. Returns None if EOF is reached before any objects.

Raises:

StopIteration

Raised at the EOF.

seek(n: int)

Seek the FileObj to the beginning of the n’th record. If IDs are set, seeks to the beginning of the record at ID, n.

tell() → int

Return ID (or offset) of next object.

truncate(size=None)

Should be implemented by subclasses and redefine this doc string.

Raises:

NotImplementedError

write(obj)

Must be implemented by subclasses that support ‘w’ subclasses Should increment .pos. Subclasses should also check if obj is an instance of type(list) and redefine this doc string.

Raises:

NotImplementedError