Object.nonull

Object.nonull 是一个假设函数，它用于判断一个对象是否为 null 或 undefined。它的作用是在访问对象的属性或调用对象的方法之前，先进行非空判断，避免抛出错误。这个函数可以通过以下方式来实现：

function nonull(obj) {
  if (obj === null || obj === undefined) {
    return false;
  } else {
    return true;
  }
}

使用该函数时，可以在需要判断的对象上调用 nonull 方法，并根据返回值来进行相应的处理。例如：

const obj = { name: "John" };

if (nonull(obj)) {
  console.log(obj.name); // 输出 "John"
} else {
  console.log("Object is null or undefined.");
}

这样就可以安全地访问对象的属性，而不用担心出现错误。注意，Object.nonull 并不是 JavaScript 内置的函数，而是一种自定义的实现方式。

相关问题

Object.Create(null)

Object.create(null) creates a new object with no prototype. This means that the new object created will not inherit any properties or methods from the Object prototype. This can be useful in scenarios where you want to create a plain object without any default properties or methods.

For example, if you want to create an object that does not have any default properties or methods and you want to add properties and methods to it manually, you can use Object.create(null) to create a new object.

Here's an example:

const myObject = Object.create(null);
myObject.name = 'John';
myObject.age = 30;

console.log(myObject); // { name: 'John', age: 30 }

In this example, we create a new object `myObject` using `Object.create(null)`. We then add two properties `name` and `age` to the object manually. Since `myObject` has no prototype, it does not inherit any default properties or methods from the Object prototype. The output of the `console.log` statement shows that `myObject` only has the two properties we added to it.

pd.DataFrame(X_missing_mean).isnull.sum()提示'function' object has no attribute 'sum'

根据您提供的信息，我猜测您可能是在调用函数时没有加括号。正确的语法是`pd.DataFrame(X_missing_mean).isnull().sum()`，其中`isnull()`和`sum()`都是函数，需要加上括号表示调用。这样就可以统计DataFrame中每一列缺失值的数量了。希望能够帮到您。