Plotting the frequencies in a FreqDist in NLTK instead of the counts.

nltk_plotfreqs.py

# Copyright (C) 2016 Martina Pugliese


def plot_freqdist_freq(fd,
                       max_num=None,
                       cumulative=False,
                       title='Frequency plot',
                       linewidth=2):
    """
    As of NLTK version 3.2.1, FreqDist.plot() plots the counts and has no kwarg for normalising to frequency. Work this around here.
    INPUT:
        - the FreqDist object
        - max_num: if specified, only plot up to this number of items (they are already sorted descending by the FreqDist)
        - cumulative: bool (defaults to False)
        - title: the title to give the plot
        - linewidth: the width of line to use (defaults to 2)
    OUTPUT: plot the freq and return None.
    """

    tmp = fd.copy()
    norm = fd.N()
    for key in tmp.keys():
        tmp[key] = float(fd[key]) / norm

    if max_num:
        tmp.plot(max_num, cumulative=cumulative,
                 title=title, linewidth=linewidth)
    else:
        tmp.plot(cumulative=cumulative, title=title, linewidth=linewidth)

    return