Extract information from a ROOT tree without using for loop

[Chris90]

I refer to extract_info where I extracted information by using a for loop. Is there a way to extract information without reading entry by entry in a for loop? for example reading the data as a matrix?

Christian

[dastudillo]

You could try with RDataFrame (documentation, tutorials).

[Chris90]

Hi,

Thanks for your answer. I solved this problem by using uproot. I found it very useful to manage arrays to create dataframe with pandas. Here, the function in python that I wrote:

def read_root_to_df (fname, treename="treename"):

    # read file, get tree and list of branches
    ntuple=uproot.open(fname)
    tree=ntuple[treename]
    col_list=tree.keys()

    # fill dict. with array from branches
    df_values = {}
    for col in col_list:
        df_values[col]=tree[col].array()

    # Create the dataframe.
    df = pd.DataFrame.from_dict(df_values)
   
    return df