问题描述
我是 python 的新手,我正在尝试定义一个函数,该函数将从特定的 city_state 返回作业令牌的 WordCloud。代码独立运行,但作为一个函数,我不知道如何修复错误。我得到一个
UnboundLocalError:赋值前引用了局部变量“comment_words”
def jobs_wordcloud(city_state):
cols = ['base_tokens']
for val in jobs_df.loc[jobs_df['city_state'] == city_state,cols]:
val = str(val)
tokens = word_tokenize(val)
tokens = re.sub('[^a-zA-Z 0-9]','',val)
tokens = tokens.lower().split()
lemmatizer = WordNetLemmatizer()
tokens = [w for w in tokens if not w in stop_words]
tokens = [lemmatizer.lemmatize(w.lower().strip()) for w in tokens]
comment_words += " ".join(tokens) + " "
wordcloud = WordCloud(width = 800,height = 800,background_color = 'white',stopwords = stop_words,min_font_size = 10).generate(comment_words)
plt.figure(figsize = (10,10),facecolor = None)
plt.imshow(wordcloud)
plt.axis("off")
plt.tight_layout(pad=0)
plt.show()
return plt.show()
这是我得到的错误:
UnboundLocalError Traceback (most recent call last)
<ipython-input-31-8df36e8cfe41> in <module>()
----> 1 jobs_wordcloud('San Francisco,CA')
<ipython-input-30-1a42912ec34f> in jobs_wordcloud(city_state)
11 tokens = [w for w in tokens if not w in stop_words]
12 tokens = [lemmatizer.lemmatize(w.lower().strip()) for w in tokens]
---> 13 comment_words += " ".join(tokens) + " "
14
15 wordcloud = WordCloud(width = 800,UnboundLocalError: local variable 'comment_words' referenced before assignment
解决方法
在 comment_words = ''
函数中开始循环之前定义 jobs_wordcloud
。
既然你在有效地执行 comment_words = comment_words + SOMETHING
,python 需要知道 comment_words 的值是什么。