uproot (originally μproot, for “micro-Python ROOT”) is a reader and a writer of the ROOT file format using only Python and NumPy. Unlike the standard C++ ROOT implementation, uproot is only an I/O library, primarily intended to stream data into machine learning libraries in Python. Unlike PyROOT and root_numpy, uproot does not depend on C++ ROOT. Instead, it uses NumPy to cast blocks of data from the ROOT file as NumPy arrays.