%matplotlib inline怎么使用

Null is a term used in computer programming to represent a value or variable that has no assigned value or is undefined. It is often used to indicate the absence of a value or a lack of data. In programming languages, null is typically represented by a keyword or symbol, such as "null" or "nil", which can be assigned to a variable to indicate that it has no value. Null values can be important in programming as they can trigger certain behaviors or conditions in an application.