代码之家 › 专栏 › 技术社区 › Sachihiro

如何将内容传递到Python中类的实例中

python-3.x python

Sachihiro · 技术社区 · 7 年前

我有一本类书,现在基本上只返回内容,但是我有一个需要读取的外部文件,然后将内容传递到该实例中, 例如,我开始将Book实例声明为b1

class Book():
    def __init__(self,poem="empty"):
        self.poem = poem

    def __str__(self):
        return self.poem

def reading(instance, file_content):
    list_of_content = []
    with open(file_content, "r") as f:
        for i in f:
            list_of_content.append(i.split())
    flatten = [item for sublist in list_of_content for item in sublist]
    string = " ".join(flatten) 
    instance = Book(string)
    return instance


b1 = Book() # book has a default value so it wont make any error
reading(b1, "file.txt")
print("File contains:",b1) # prints empty, because reading function has not passed any data i think

问题是,现在它总是只打印“空的”,我如何将从文件中读取的数据传递给在reading()中调用的实例,这是为了学习。

3 回复 | 直到 7 年前

Mark Tolonen 7 年前

reading 应该是类的一个方法,但也可以初始化 Book 创建时:

class Book():

    def __init__(self,filename):
        list_of_content = []
        with open(filename) as f:
            for line in f:
                list_of_content.append(line.split())
        flatten = [item for sublist in list_of_content for item in sublist]
        string = " ".join(flatten) 
        self.poem = string

    def __str__(self):
        return self.poem

b1 = Book('file.txt')
print("File contains:",b1)

如果您仍然想创建空的书籍,并可能将不同的文件读取到同一本书中 书 制作 read 一种方法:

class Book():
    def __init__(self,poem='<empty>'):
        self.poem = poem

    def read(self,filename):        
        list_of_content = []
        with open(filename) as f:
            for line in f:
                list_of_content.append(line.split())
        flatten = [item for sublist in list_of_content for item in sublist]
        string = " ".join(flatten) 
        self.poem = string

    def __str__(self):
        return self.poem

b1 = Book()
print("File contains:",b1)
b1.read('file.txt')
print("File now contains:",b1)

Vasyl Kushnir 7 年前

用于创建具有一些附加功能的实例,例如常用的类方法 https://www.programiz.com/python-programming/methods/built-in/classmethod

试试这个:

class Book():
def __init__(self,poem="empty"):
    self.poem = poem

@classmethod
def load_book(cls, filename):
    list_of_content = []
    with open(filename, "r") as input_file:
        for line in input_file:
            list_of_content.append(line.split())
        flatten = [item for sublist in list_of_content for item in sublist]
        string = " ".join(flatten) 
        book_inst = cls(string)
        return book_inst

def __str__(self):
    return self.poem


book = Book.load_book("input.txt")
print(book)

Bitto 7 年前

class Book():
    def __init__(self,poem="empty"):
        self.poem = poem

    def __str__(self):
        return self.poem

def reading(self, file_content):
    list_of_content = []
    with open(file_content, "r") as f:
        for i in f:
            list_of_content.append(i.split())
    flatten = [item for sublist in list_of_content for item in sublist]
    string = " ".join(flatten)
    self.poem=string


b1 = Book() 
reading(b1, "file.txt")
print("File contains:",b1)

产量

File contains: I really love christmas Keep the change ya filthy animal Pizza is my fav food Did someone say peanut butter?