LazyDataFrame

class coffea.processor.LazyDataFrame(tree, entrystart=None, entrystop=None, preload_items=None, metadata=None)[source]

Bases: MutableMapping

Simple delayed uproot reader (a la lazyarrays)

One can access branches either through df["bname"] or df.bname, although the latter is restricted to branches that do not start with a leading underscore. Keeps track of values accessed, in the materialized attribute.

Parameters:

tree (uproot.TTree) – Tree to read
entrystart (int, optional) – First entry to read, default: 0
entrystop (int, optional) – Last entry to read, default None (read to end)
preload_items (iterable) – Force preloading of a set of columns from the tree
metadata (Mapping) – Additional metadata for the dataframe

Attributes Summary

`available`	Set of available columns
`columns`	Set of available columns
`materialized`	Set of columns read from tree
`metadata`
`size`	Length of column vector

Methods Summary

preload(columns)

Force loading of several columns

Attributes Documentation

available: Set of available columns

columns: Set of available columns

materialized: Set of columns read from tree

metadata

size: Length of column vector

Methods Documentation

preload(columns)[source]

Force loading of several columns

Parameters:: columns (iterable) – A list of columns to load