通过 Python 中的方法进行字符串操作

String Manipulation through methods in Python

从 class 句子开始,我正在尝试创建多种方法来打印字符串中的所有单词,return 索引中的单词,以及替换索引中的单词(和更多)。我无法理解 self 在整个方法中的使用以及最后的调用方法。

class Sentence:
    def __init__(self, sentence = ''):
        '''default value for private attribute (sentence) = empty string'''
        self._sentence_str = sentence
    def get_all_words(self):
        '''return all words in the sentence as a list'''
        self.s.split(" ")
        return self.s    
    def get_word(self, param):
        '''return only the word at a particular index'''
        '''arguments = index'''
        #Here, do I return an empty index so that I can call it/pick an index 
         at the end?
_sentence = Sentence("It feels like fall today")
print(_sentence)
index = self.index[2] #something like this? and print it?
    def __init__(self, sentence=''):
        
        '''default value for private attribute (sentence) = empty string'''
        self.sentence_str = sentence
    def get_all_words(self):
        '''return all words in the sentence as a list'''
        list = self.sentence_str.split(" ")
        return list    
        
    def get_word(self, index):
        '''return only the word at a particular index'''
        list = self.get_all_words() #split
        return list[index]  #this is how you access a list item by it's index: list[index]

    def replace_word(self, word, new_word):
        list = self.get_all_words()   # split
        current_word_index = list.index(word) #find in what index the word you want to change lives
        list[current_word_index] = new_word # replace the current word in current_word_index with the new word
        return ' '.join(list) #optional: you can return an actual string instead of a list, use return list if you want a list
        
        
sentence = Sentence("It feels like fall today")

print(sentence.get_all_words()) #this will return the string as a list
print(sentence.get_word(2)) # this will return an item at a certain index
print(sentence.replace_word('fall', 'summer')) #this will replace a word

你不能简单地 return self.s,你应该 return 整个 self.sentence_str.split(" ") 或者像我一样将它分配给一个变量,但这没有任何区别。