找不到 'cairo.Context' 的外部结构转换器

Question

又是我。这是与我正在做的项目相关的代码，称为 Twitter 数据上的情绪分析。以下代码基本上用于显示出现以下错误的正面和负面推文的数量。

from pyspark import SparkConf, SparkContext
from pyspark.streaming import StreamingContext
from pyspark.streaming.kafka import KafkaUtils
import operator
import numpy as np
import matplotlib.pyplot as plt


def main():
        conf = SparkConf().setMaster("local[2]").setAppName("Streamer")
        sc = SparkContext(conf=conf)

        # Creating a streaming context with batch interval of 10 sec
        ssc = StreamingContext(sc, 10)
        ssc.checkpoint("checkpoint")
        pwords = load_wordlist("positive.txt")
        nwords = load_wordlist("negative.txt")
        counts = stream(ssc, pwords, nwords, 100)
        make_plot(counts)


def make_plot(counts):
        """
        This function plots the counts of positive and negative words for each timestep.
        """
        positiveCounts = []
        negativeCounts = []
        time = []

        for val in counts:
        positiveTuple = val[0]
        positiveCounts.append(positiveTuple[1])
        negativeTuple = val[1]
        negativeCounts.append(negativeTuple[1])

        for i in range(len(counts)):
        time.append(i)

        posLine = plt.plot(time, positiveCounts,'bo-', label='Positive')
        negLine = plt.plot(time, negativeCounts,'go-', label='Negative')
        plt.axis([0, len(counts), 0, max(max(positiveCounts), max(negativeCounts))+50])
        plt.xlabel('Time step')
        plt.ylabel('Word count')
        plt.legend(loc = 'upper left')
    plt.show()


def load_wordlist(filename):
    """ 
    This function returns a list or set of words from the given filename.
    """ 
    words = {}
    f = open(filename, 'rU')
    text = f.read()
    text = text.split('\n')
    for line in text:
        words[line] = 1
    f.close()
    return words


def wordSentiment(word,pwords,nwords):
    if word in pwords:
    return ('positive', 1)
    elif word in nwords:
    return ('negative', 1)


def updateFunction(newValues, runningCount):
    if runningCount is None:
       runningCount = 0
    return sum(newValues, runningCount) 


def sendRecord(record):
    connection = createNewConnection()
    connection.send(record)
    connection.close()


def stream(ssc, pwords, nwords, duration):
    kstream = KafkaUtils.createDirectStream(
    ssc, topics = ['twitterstream'], kafkaParams = {"metadata.broker.list": 'localhost:9092'})
    tweets = kstream.map(lambda x: x[1].encode("ascii", "ignore"))

    # Each element of tweets will be the text of a tweet.
    # We keep track of a running total counts and print it at every time step.
    words = tweets.flatMap(lambda line:line.split(" "))
    positive = words.map(lambda word: ('Positive', 1) if word in pwords else ('Positive', 0))
    negative = words.map(lambda word: ('Negative', 1) if word in nwords else ('Negative', 0))
    allSentiments = positive.union(negative)
    sentimentCounts = allSentiments.reduceByKey(lambda x,y: x+y)
    runningSentimentCounts = sentimentCounts.updateStateByKey(updateFunction)
    runningSentimentCounts.pprint()

    # The counts variable hold the word counts for all time steps
    counts = []
    sentimentCounts.foreachRDD(lambda t, rdd: counts.append(rdd.collect()))

    # Start the computation
    ssc.start() 
    ssc.awaitTerminationOrTimeout(duration)
    ssc.stop(stopGraceFully = True)

    return counts


if __name__=="__main__":
    main()

正好报错如下：

Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_gtk3.py", line 343, in idle_draw
    self.draw()
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_gtk3.py", line 336, in draw
    self.get_property("window").process_updates (False)
TypeError: Couldn't find foreign struct converter for 'cairo.Context'

Answer 1

这里的问题是matplotlib的后端GTK3。我建议将其更改为适合您的后端。参见 https://matplotlib.org/faq/usage_faq.html

我经常

import matplotlib
matplotlib.use('Agg')

在任何与 matplotlib 相关的导入之前。您将看不到图形，但可以使用 savefig() 保存它，然后使用图像查看器打开它。

Answer 2

看到这个Github discussion。例如尝试：

sudo apt-get install python-gi-cairo

Answer 3

回复上述评论，3 年后（我使用 WSL 2 和 VSCode，以及用于 GUI 应用程序的 X-server），你应该使用

sudo apt install python3-gi-cairo

并且您省去了更改后端的麻烦。

Answer 4

在我的例子中，python3-gi-cairo 已经安装但可能已损坏。因此，如果有人遇到这种情况，您只需在 apt 安装中添加 --reinstall。

sudo apt install --reinstall python3-gi-cairo

在此处重新安装不会破坏您的系统，因为当您删除（所有依赖项也将被删除）然后再次安装时。

找不到 'cairo.Context' 的外部结构转换器

Couldn't find foreign struct converter for 'cairo.Context'

python

pycairo

pyspark