Question

我正在使用麻省理工学院的开放式课件学习python，其中一个问题是学习如何使用类来搜索感兴趣的主题的RSS源。我不知道为什么我收到下面显示的错误。我试图将搜索单词字符串和字符串从新闻故事对象转换为全部小写，然后尝试查找单词 - 如果搜索单词是“软”那么就会触发，那么触发器应该触发在诸如“考拉”之类的字符串上，它们是柔软而可爱的。而且“软砂纸”也没有效果。

import string

class NewsStory(object):
    #news story is defined by 5 strings: guid, title, subject, summary, and link
    def __init__(self, guid, title, subject, summary, link):
        self.guid = guid
        self.title = title
        self.subject = subject
        self.summary = summary
        self.link = link
    def get_guid(self):
        return self.guid
    def get_title(self):
        return self.title
    def get_subject(self):
        return self.subject
    def get_summary(self):
        return self.summary
    def get_link(self):
        return self.link

class Trigger(object):
    #abstract class
    def evaluate(self, story):
        """
        Returns True if an alert should be generated
        for the given news item, or False otherwise.
        """
        raise NotImplementedError

# Whole Word Triggers
# Problems 2-5

# TODO: WordTrigger
class WordTrigger(Trigger):
    def __init__(self, word):
        #make search word all lowercase to remove case sensitivity
        self.word = string.lower(word)

    def is_word_in(self, text):
        #make text string from news story all lowercase to remove case sensitivity
        self.text = string.lower(text)
        #use the find method of the string class
        #it returns the lowest index where substring s is found in string; returns -1 if substring not found
        return string.find(self.text, self.word) > -1

# TODO: TitleTrigger, this subclass of WordTrigger will trigger on search term that is found in the title string of the news story object
class TitleTrigger(WordTrigger):
    def __init__(self, word):
        self.word = string.lower(word)

    def evaluate(self, story):
        #story is an instance of the NewsStory class
        title = story.get_title
        return super(TitleTrigger, self).is_word_in(title)

#make news story object
news1 = NewsStory('1234','it is raining dogs and cats','animals falling from sky','3 dogs and 2 cats fell from sky','www.cat.com')
#make TitleTrigger object
testTrig = TitleTrigger('cats')
testTrig.evaluate(news1)

我正在摸不着头脑的错误如下所示：

>>> 

Traceback (most recent call last):
  File "C:/Users/David/Documents/Python2_7/Unit 2/postonline.py", line 61, in <module>
    testTrig.evaluate(news1)
  File "C:/Users/David/Documents/Python2_7/Unit 2/postonline.py", line 55, in evaluate
    return super(TitleTrigger, self).is_word_in(title)
  File "C:/Users/David/Documents/Python2_7/Unit 2/postonline.py", line 42, in is_word_in
    self.text = string.lower(text)
  File "C:\WinPython-64bit-2.7.10.3\python-2.7.10.amd64\lib\string.py", line 228, in lower
    return s.lower()
AttributeError: 'function' object has no attribute 'lower'

搜索字符串时删除区分大小写的问题

0 个答案: