Getting output in parquet format from Uproot

[michmx]

I would like to read a .root file with uproot, and get a parquet file. How can I do that?

[hep-helper[bot]]

Potentially useful sources

17 August, 2020: GitHub issue scikit-hep/awkward#393, Unintuitive results working with nullable data (from parquet)

Score: 90 out of 100

The conversation provides a detailed discussion on reading from a .root file with uproot, converting it to a parquet file, and handling nullable values in the resulting arrays. You can refer to the examples of using ak.to_parquet and ak.from_parquet functions, as well as dealing with BitMaskedArrays and converting them to ByteMaskedArrays for proper handling of ufuncs like >. This information can be useful for understanding the process of converting ROOT files to parquet.

22 June, 2022: GitHub discussion scikit-hep/awkward#1512, How to change the output parquet file with jagged array to root file?

Score: 90 out of 100

The conversation provides information on how to read a .root file with uproot and extract data from a TTree. You can use the examples provided in the conversation to understand how to access and extract data from a TTree using uproot. Look for the examples demonstrating how to read a branch from a TTree using uproot and how to iterate over the entries in a TTree to extract the data. This information will be helpful in converting the data from a .root file to a parquet file.

20 August, 2020: GitHub issue scikit-hep/awkward#395, Sliced arrays yields inconsistent values in numba jitted function

Score: 85 out of 100

The conversation provides a detailed explanation of a bug related to handling IndexedArray within ListOffsetArray in Numba, which may not directly answer your question but gives insight into potential issues when working with arrays. Look for examples of code snippets using ListOffsetArray and IndexedArray, as well as discussions on how the bug manifests itself. This information can help you understand potential challenges when reading a .root file with uproot and converting it to a parquet file.

3 December, 2019: GitHub discussion scikit-hep/awkward#27, Using Awkward Arrays in or with Xarray

Score: 75 out of 100

The conversation discusses reading ROOT files with uproot and converting them to Parquet files using Awkward Arrays. It mentions functions like ak.to_parquet and ak.from_parquet, which go through pyarrow, as well as Arrow itself. Look for examples of using these functions and how they preserve nested data structures. Additionally, the conversation touches on the integration of Awkward Arrays with other storage formats like HDF5 and Zarr, which could be helpful in understanding the broader context of file I/O with Awkward Arrays.

9 July, 2022: GitHub discussion scikit-hep/uproot5#648, Memory management issues

Score: 60 out of 100

The conversation discusses memory management and efficient loading of data from ROOT files using uproot, which can be helpful in understanding how to handle large files. Look for examples of lazy loading, setting object_cache=None, and using coffea processors to efficiently process data without loading everything into memory at once. These concepts can be applied to your task of reading a .root file with uproot and converting it to a parquet file.

22 September, 2021: GitHub discussion scikit-hep/uproot5#448, Leaf-lists (structs) and non-leaf-lists in the same Pandas DataFrame

Score: 25 out of 100

The conversation provides information on reading root files with uproot and manipulating data frames in pandas. While it doesn't directly address converting a root file to a parquet file, it does show how to read root files into pandas data frames, which is a step in the process. Look for examples of using uproot to read root files into pandas data frames and how to manipulate the data frames, as this knowledge can be applied to converting to a parquet file.