hist_utils.py

#!/usr/bin/env python3
 
 
 
import numpy as np
 
 
def hist2array(hist, return_edges=False):
    """
    Function to convert a histogram into a numpy array and optionally also
    return a list of the bin edges
    Parameters:
        hist: one-dimensional histogram
        return_edges (bool): flag whether bin edges should be calculated and returned
    Return:
        numpy array and optionally a list of the bin edges
    """
    nbins = hist.GetNbinsX()
    arr = np.zeros(nbins)
    for i in range(nbins):
        arr[i] = hist.GetBinContent(i + 1)
    if return_edges:
        edges = []
        edges.append(np.empty(nbins + 1))
        hist.GetXaxis().GetLowEdge(edges[-1])
        edges[-1][nbins] = hist.GetXaxis().GetBinUpEdge(nbins)
        return arr, edges
    return arr
 
 
def array2hist(array, hist):
    """
    Function to fill a histogram from an array
    Parameters:
        array: array
        hist: histogram
    """
    ndim = array.ndim
    if ndim == 1:
        nbins = len(array)
        for i in range(nbins):
            hist.SetBinContent(i + 1, array[i])
    elif ndim == 2:
        for i in range(hist.GetNbinsX()):
            for j in range(hist.GetNbinsY()):
                hist.SetBinContent(i + 1, j + 1, array[i, j])