def dispersion_plot(text, words, ignore_case=False, title="Lexical Dispersion Plot"):
    """
    Generate a lexical dispersion plot.

    :param text: The source text
    :type text: list(str) or enum(str)
    :param words: The target words
    :type words: list of str
    :param ignore_case: flag to set if case should be ignored when searching text
    :type ignore_case: bool
    """

    try:
        from matplotlib import pylab
    except __HOLE__:
        raise ValueError('The plot function requires matplotlib to be installed.'
                     'See http://matplotlib.org/')

    text = list(text)
    words.reverse()

    if ignore_case:
        words_to_comp = list(map(str.lower, words))
        text_to_comp = list(map(str.lower, text))
    else:
        words_to_comp = words
        text_to_comp = text

    points = [(x,y) for x in range(len(text_to_comp))
                    for y in range(len(words_to_comp))
                    if text_to_comp[x] == words_to_comp[y]]
    if points:
        x, y = list(zip(*points))
    else:
        x = y = ()
    pylab.plot(x, y, "b|", scalex=.1)
    pylab.yticks(list(range(len(words))), words, color="b")
    pylab.ylim(-1, len(words))
    pylab.title(title)
    pylab.xlabel("Word Offset")
    pylab.show()
dataset/ETHPy150Open nltk/nltk/nltk/draw/dispersion.py/dispersion_plot