Impossible de trouver le convertisseur de structure étrangère pour 'cairo.Context'

Question

C'est encore moi. Ceci est un code lié à un projet que je fais appelé Sentiment Analysis on Twitter Data. Le code suivant est essentiellement utilisé pour afficher le nombre de tweets positifs et négatifs dans lesquels j'obtiens l'erreur donnée ci-dessous.

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() 

L'erreur se trouve être comme suit:

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

Le problème ici est de back-end matplotlib de GTK3. Je recommande de le changer pour un backend qui fonctionne juste pour vous. Voir https://matplotlib.org/faq/usage_faq.html

que je fais habituellement

import matplotlib 
matplotlib.use('Agg') 

avant toute importation liée à Matplotlib. Vous ne serez pas en mesure de voir la figure mais vous pouvez l'enregistrer avec savefig() et l'ouvrir ensuite avec votre visionneuse d'image.