Source code for nltk.draw.dispersion

# Natural Language Toolkit: Dispersion Plots
# Copyright (C) 2001-2021 NLTK Project
# Author: Steven Bird <>
# URL: <>
# For license information, see LICENSE.TXT

A utility for displaying lexical dispersion.

[docs]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 ImportError as e: raise ValueError( "The plot function requires matplotlib to be installed." "See" ) from e 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=0.1) pylab.yticks(list(range(len(words))), words, color="b") pylab.ylim(-1, len(words)) pylab.title(title) pylab.xlabel("Word Offset")
if __name__ == "__main__": from nltk.corpus import gutenberg words = ["Elinor", "Marianne", "Edward", "Willoughby"] dispersion_plot(gutenberg.words("austen-sense.txt"), words)