Question

我正在尝试编写一个清理URL的功能（将它们删除像＆＃34; www。＆＃34;，＆＃34; http：//＆＃34;等等）以创建列表我可以按字母顺序排序。

我试图通过创建一个类来实现这一点，该类包含一个方法来检测我想从URL字符串中删除的术语，并将其删除。我正在努力的一点是，我想将修改后的URL添加到名为new_strings的新列表中，然后在我在另一个术语上第二次调用该方法时使用该新列表，以便逐步执行步骤我可以从URL字符串中删除所有不需要的元素。

由于某些原因，我当前的代码返回一个空列表，我也在努力了解new_strings是否应该传递给__init__？我想我对全局变量和局部变量有点困惑，一些帮助和解释将非常感激。：）

谢谢！代码如下。

class URL_Cleaner(object):
    def __init__(self, old_strings, new_strings, term):
        self.old_strings = old_strings
        self.new_strings = new_strings
        self.term = term

    new_strings = []

    def delete_term(self, new_strings):
        for self.string in self.old_strings:
            if self.term in string:
                new_string = string.replace(term, "")
                self.new_strings.append(new_string)
            else:
                self.new_strings.append(string)
        return self.new_strings

    print "\n" .join(new_strings) #for checking; will be removed later

strings = ["www.google.com", "http://www.google.com", "https://www.google.com"]
new_strings = []
www = URL_Cleaner(strings, new_strings, "www.")

Answer 1

我们为什么要上课呢？

for string in strings:
     string.replace("www.","")

这不是你想要完成的吗？

无论问题出在您的班级定义中。注意范围：

class URL_Cleaner(object):
    def __init__(self, old_strings, new_strings, term):
        """These are all instance objects"""
        self.old_strings = old_strings
        self.new_strings = new_strings
        self.term = term

    new_strings = [] # this is a class object

    def delete_term(self, new_strings):
        """You never actually call this function! It never does anything!"""
        for self.string in self.old_strings:
            if self.term in string:
                new_string = string.replace(term, "")
                self.new_strings.append(new_string)
            else:
                self.new_strings.append(string)
        return self.new_strings

    print "\n" .join(new_strings) #for checking; will be removed later
    # this is referring the class object, and will be evaluated when
    # the class is defined, NOT when the object is created!

我已经为您的代码评论了必要的原因....要修复：

class URL_Cleaner(object):
    def __init__(self, old_strings):
        """Cleans URL of 'http://www.'"""
        self.old_strings = old_strings
        cleaned_strings = self.clean_strings()
    def clean_strings(self):
        """Clean the strings"""
        accumulator = []
        for string in self.old_strings:
            string = string.replace("http://", "").replace("www.", "")
            # this might be better as string = re.sub("http://(?:www.)?", "", string)
            # but I'm not going to introduce re yet.
            accumulator.append(string)
        return accumulator
        # this whole function is just:
        ## return [re.sub("http://(?:www.)?", "", string, flags=re.I) for string in self.old_strings]
        # but that's not as readable imo.

Answer 2

您只需要将new_strings定义为

self.new_strings = []

并从构造函数中删除new_strings参数。

＆＃39; new_strings＆＃39;和＆＃39; self.new_strings＆＃39;是两个不同的列表。

类返回空列表

2 个答案: