将列表附加到类对象（python）

Question

无法使用以下类执行以下代码：

预期结果 = [1, 2, 3, 4, 90, 25] 给定结果 = ma​​in.ArrayList object at 0x7f9f1439acd0>

我怎样才能阻止这种情况发生？没有内置的extend()

任何帮助表示赞赏

class ArrayList:
    def __init__(self):
        self.inArray = []
        self.count = 0

    def appendAll(self, e):
        newArray = [0 for i in range(len(self.inArray)+1)]
        for i in range(len(self.inArray)):
            newArray[i] = self.inArray[i]
            newArray[len(self.inArray)] = e
            self.inArray = newArray

ls = [1, 2, 3, 4]
ls = ArrayList()
ls.appendAll([90, 25])
print(ls)

Answer 1

这是因为 Python 默认返回对用户定义的类对象的引用，而不是它的数据成员。

这就是我认为你想要实现的...

class ArrayList:
    def __init__(self, inArray: list = []):
        self.inArray = inArray
        self.count : int = 0

    def appendAll(self, newArray: list):
        self.inArray.extend(newArray)   # extend() can add multiple values at a time
    
    def __str__(self):                  # __str__ is a magic/dunder method (Special function reserved in Python which gets activated when you try to print an object of it's class)
        return str(self.inArray)


if __name__=='__main__':
    ls = ArrayList([1, 2, 3, 4])    # Initialize ArrayList object with default value
    ls.appendAll([90, 25])          # Add more values
    print(ls)

我已经更正了您的代码，并为您添加了以下概念：
1 Type-Hinting
2.'ma​​in'函数