uproot.open

Defined in uproot.reading on line 23.

uproot.reading.open(path, object_cache=100, array_cache='100 MB', custom_classes=None, decompression_executor=None, interpretation_executor=None, **options)
Parameters
  • path (str or pathlib.Path) – The filesystem path or remote URL of the file to open. If a string, it may be followed by a colon (:) and an object path within the ROOT file, to return an object, rather than a file. Path objects are interpreted strictly as filesystem paths or URLs. Examples: "rel/file.root", "C:\abs\file.root", "http://where/what.root", "https://username:password@where/secure.root", "rel/file.root:tdirectory/ttree", Path("rel:/file.root"), Path("/abs/path:stuff.root")

  • object_cache (None, MutableMapping, or int) – Cache of objects drawn from ROOT directories (e.g histograms, TTrees, other directories); if None, do not use a cache; if an int, create a new cache of this size.

  • array_cache (None, MutableMapping, or memory size) – Cache of arrays drawn from TTrees; if None, do not use a cache; if a memory size, create a new cache of this size.

  • custom_classes (None or MutableMapping) – If None, classes come from uproot.classes; otherwise, a container of class definitions that is both used to fill with new classes and search for dependencies.

  • decompression_executor (None or Executor with a submit method) – The executor that is used to decompress TBaskets; if None, a uproot.TrivialExecutor is created. Executors attached to a file are shutdown when the file is closed.

  • interpretation_executor (None or Executor with a submit method) – The executor that is used to interpret uncompressed TBasket data as arrays; if None, a uproot.TrivialExecutor is created. Executors attached to a file are shutdown when the file is closed.

  • options – See below.

Opens a ROOT file, possibly through a remote protocol.

If an object path is given, the return type of this function can be anything that can be extracted from a ROOT file (subclass of uproot.Model).

If an object path is not given, the return type is a uproot.ReadOnlyDirectory and not uproot.ReadOnlyFile. ROOT objects can be extracted from a uproot.ReadOnlyDirectory but not a uproot.ReadOnlyFile.

Options (type; default):

Any object derived from a ROOT file is a context manager (works in Python’s with statement) that closes the file when exiting the with block. Therefore, the uproot.open function can and usually should be used in a with statement to clean up file handles and threads associated with open files:

with uproot.open("/path/to/file.root:path/to/histogram") as h:
    h.to_hist().plot()

# file is now closed, even if an exception was raised in the block

Other file entry points:

For remote ROOT files served over HTTP(S), basic authentication is supported. In this case, the credentials may be provided part of the URL in, as in https://username:password@example.org/secure/protected.root. Note that for security reasons, it is recommended basic authentication only be used for HTTPS resources.