Python NLTK 文本离散图有 y 垂直轴是向后/反向顺序

我找到了nltk.draw.dispersion的源代码，但似乎有错误。

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 iter(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
    :return: a matplotlib Axes object that may still be modified before plotting
    :rtype: Axes
    """

    try:
        import matplotlib.pyplot as plt
    except ImportError as e:
        raise ImportError(
            "The plot function requires matplotlib to be installed. "
            "See https://matplotlib.org/"
        ) from e

    word2y = {
        word.casefold() if ignore_case else word: y
        for y, word in enumerate(reversed(words))  # <--- HERE
    }
    xs, ys = [], []
    for x, token in enumerate(text):
        token = token.casefold() if ignore_case else token
        y = word2y.get(token)
        if y is not None:
            xs.append(x)
            ys.append(y)

    _, ax = plt.subplots()
    ax.plot(xs, ys, "|")
    ax.set_yticks(list(range(len(words))), words, color="C0")  # <--- HERE
    ax.set_ylim(-1, len(words))
    ax.set_title(title)
    ax.set_xlabel("Word Offset")
    return ax



if __name__ == "__main__":
    import matplotlib.pyplot as plt

    from nltk.corpus import gutenberg

    words = ["Elinor", "Marianne", "Edward", "Willoughby"]
    dispersion_plot(gutenberg.words("austen-sense.txt"), words)
    plt.show()

它使用word2yreversed(words)

for y, word in enumerate(reversed(words))

但后来它使用 using 但它应该使用ax.set_yticks()wordsreversed(words)

ax.set_yticks(list(range(len(words))), words, color="C0")

（或者它应该在不使用 的情况下计算）。word2yreversed()

我在上面的代码中添加了这些地方。# <--- HERE

它可能需要将其报告为问题。

此时，您可以获取并使用来纠正它。
在您的代码中，它将代替axset_yticksreversedtargetswords

ax = dispersion_plot(words, targets)

ax.set_yticks(list(range(len(targets))), reversed(targets), color="C0")

完整的工作代码

import matplotlib.pyplot as plt
from nltk.draw.dispersion import dispersion_plot

words = ['aa','aa','aa','bbb','cccc','aa','bbb','aa','aa','aa','cccc','cccc','cccc','cccc']
targets = ['aa','bbb', 'f', 'cccc']

ax = dispersion_plot(words, targets)
ax.set_yticks(list(range(len(targets))), reversed(targets), color="C0")

plt.show()

编辑：我似乎几个月前报告了这个问题，他们在 GitHub 上添加了代码 - 它可能在下一个版本中起作用reversed()

色散图工作不正常 ·期刊 #3133 ·NLTK/NLTK系列

色散图无法正常工作 由 Apros7 ·拉取请求 #3134 ·NLTK/NLTK系列

根据@furas答案❤️，我更进一步并添加了一个 if 条件，只有在它们确实被破坏/向后时才会反转 y 刻度。这意味着一旦他们修复了库错误（即将修复），代码仍将有效。

from nltk.draw.dispersion import dispersion_plot
targets=['a', 'b']
filtered_text = ["a","a","b"]
my_plot = dispersion_plot(filtered_text, targets, ignore_case=True)

# THIS IS NEW: if targets are wrong, fix them (reverse them)
if [label.get_text() for label in my_plot.get_yticklabels()] != reversed(targets):
    my_plot.set_yticks(list(range(len(targets))), reversed(targets))

plt.show()

（我在本地修复了图形库，并用新版本对其进行了测试，代码适用于旧的损坏库和新修复的库）