Defined in uproot.behaviors.TBranch on line 48.

uproot.behaviors.TBranch.iterate(files, expressions=None, cut=None, *, filter_name=<function no_filter>, filter_typename=<function no_filter>, filter_branch=<function no_filter>, aliases=None, language=uproot.language.python.PythonLanguage(), step_size='100 MB', decompression_executor=None, interpretation_executor=None, library='ak', ak_add_doc=False, how=None, report=False, custom_classes=None, allow_missing=False, **options)
  • files – See below.

  • expressions (None, str, or list of str) – Names of TBranches or aliases to convert to arrays or mathematical expressions of them. Uses the language to evaluate. If None, all TBranches selected by the filters are included.

  • cut (None or str) – If not None, this expression filters all of the expressions.

  • filter_name (None, glob string, regex string in "/pattern/i" syntax, function of str → bool, or iterable of the above) – A filter to select TBranches by name.

  • filter_typename (None, glob string, regex string in "/pattern/i" syntax, function of str → bool, or iterable of the above) – A filter to select TBranches by type.

  • filter_branch (None or function of uproot.TBranch → bool, uproot.interpretation.Interpretation, or None) – A filter to select TBranches using the full uproot.TBranch object. If the function returns False or None, the TBranch is excluded; if the function returns True, it is included with its standard interpretation; if an uproot.interpretation.Interpretation, this interpretation overrules the standard one.

  • aliases (None or dict of str → str) – Mathematical expressions that can be used in expressions or other aliases (without cycles). Uses the language engine to evaluate. If None, only the aliases are available.

  • language (uproot.language.Language) – Language used to interpret the expressions and aliases.

  • step_size (int or str) – If an integer, the maximum number of entries to include in each iteration step; if a string, the maximum memory size to include. The string must be a number followed by a memory unit, such as “100 MB”.

  • decompression_executor (None or Executor with a submit method) – The executor that is used to decompress TBaskets; if None, a uproot.TrivialExecutor is created.

  • 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.

  • library (str or uproot.interpretation.library.Library) – The library that is used to represent arrays. Options are "np" for NumPy, "ak" for Awkward Array, and "pd" for Pandas.

  • ak_add_doc (bool) – If True and library="ak", add the TBranch title to the Awkward __doc__ parameter of the array.

  • how (None, str, or container type) – Library-dependent instructions for grouping. The only recognized container types are tuple, list, and dict. Note that the container type itself must be passed as how, not an instance of that type (i.e. how=tuple, not how=()).

  • report (bool) – If True, this generator yields (arrays, uproot.behaviors.TBranch.Report) pairs; if False, it only yields arrays. The report has data about the TFile, TTree, and global and local entry ranges.

  • custom_classes (None or dict) – If a dict, override the classes from the uproot.ReadOnlyFile or uproot.classes.

  • allow_missing (bool) – If True, skip over any files that do not contain the specified TTree.

  • options – See below.

Iterates through contiguous chunks of entries from a set of files.

For example:

>>> for array in uproot.iterate("files*.root:tree", ["x", "y"], step_size=100):
...     # each of the following have 100 entries
...     array["x"], array["y"]

Allowed types for the files parameter:

  • str/bytes: relative or absolute filesystem path or URL, without any colons other than Windows drive letter or URL schema. Examples: "rel/file.root", "C:\abs\file.root", "http://where/what.root"

  • str/bytes: same with an object-within-ROOT path, separated by a colon. Example: "rel/file.root:tdirectory/ttree"

  • pathlib.Path: always interpreted as a filesystem path or URL only (no object-within-ROOT path), regardless of whether there are any colons. Examples: Path("rel:/file.root"), Path("/abs/path:stuff.root")

  • glob syntax in str/bytes and pathlib.Path. Examples: Path("rel/*.root"), "/abs/*.root:tdirectory/ttree"

  • dict: keys are filesystem paths, values are objects-within-ROOT paths. Example: {{"/data_v1/*.root": "ttree_v1", "/data_v2/*.root": "ttree_v2"}}

  • already-open TTree objects.

  • iterables of the above.

Options (type; default):

  • handler (uproot.source.chunk.Source class; None)

  • timeout (float for HTTP, int for XRootD; 30)

  • max_num_elements (None or int; None)

  • num_workers (int; 1)

  • use_threads (bool; False on the emscripten platform (i.e. in a web browser), else True)

  • num_fallback_workers (int; 10)

  • begin_chunk_size (memory_size; 403, the smallest a ROOT file can be)

  • minimal_ttree_metadata (bool; True)

See also iterate to iterate within a single file.

Other file entry points:

  • uproot.open: opens one file to read any of its objects.

  • uproot.iterate (this function): iterates through chunks of contiguous entries in TTrees.

  • uproot.concatenate: returns a single concatenated array from TTrees.

  • uproot.dask: returns an unevaluated Dask array from TTrees.