Python 如何通过引用更改变量，如Pandas inplace

因此，我在与Pandas合作时，最近遇到了inplace参数，它可以在不重新赋值的情况下更改原始变量

示例：

df.dropna（inplace=True）

而不是

df=df.dropna（）

我想应用相同的机制，但用于自定义函数。但是，本机仅支持

列表

类型

def append(x, element):
    x.append(element)

如果我尝试使用其他类型，它将不起作用

def to_lower(text):
    text.lower()

---

有人知道Pandas

inplace

是如何完成这项工作的吗？

我认为

inplace=True

vs

inplace=False

可以通过正确定义

\u repr\u

方法在课堂上实现：

class ToLower:

    def __init__(self, text: str):
        self.text = text

    def to_lower(self, inplace: bool):
        self.text = self.text.lower()
        if not inplace:
            return self

    def __repr__(self):
        return f"{self.text}"

# not in place
example = ToLower("Hello World!")
print("Input value NOT in place :", example)
out = example.to_lower(inplace=False)
print("Input value after NOT in place:", example)
print("Returned after NOT in place:", out)
# update in place
example = ToLower("Hello World!")
print("Input value in place:", example)
out = example.to_lower(inplace=True)
print("Input value after in place:", example)
print("Returned after in place:", out)
text = "LET'S TRY ONE MORE TIME"
example = ToLower(text)
example.to_lower(inplace=True)
print("Desired output:", example)

---

---

@AmineMessaoudi我想知道这是否有助于解决您的问题

text = 'Hello World'
to_lower(text)
text
'Hello World'

class ToLower:

    def __init__(self, text: str):
        self.text = text

    def to_lower(self, inplace: bool):
        self.text = self.text.lower()
        if not inplace:
            return self

    def __repr__(self):
        return f"{self.text}"

# not in place
example = ToLower("Hello World!")
print("Input value NOT in place :", example)
out = example.to_lower(inplace=False)
print("Input value after NOT in place:", example)
print("Returned after NOT in place:", out)
# update in place
example = ToLower("Hello World!")
print("Input value in place:", example)
out = example.to_lower(inplace=True)
print("Input value after in place:", example)
print("Returned after in place:", out)
text = "LET'S TRY ONE MORE TIME"
example = ToLower(text)
example.to_lower(inplace=True)
print("Desired output:", example)

Input value NOT in place : Hello World!
Input value after NOT in place: hello world!
Returned after NOT in place: hello world!
Input value in place: Hello World!
Input value after in place: hello world!
Returned after in place: None
Desired output: let's try one more time