For a language-agnostic consideration of the design decision, see What is the advantage of having this/self pointer mandatory explicit?. To close debugging questions where OP omitted a self parameter for a method and got a TypeError, use TypeError: method () takes 1 positional argument but 2 were given instead. If OP omitted self. in the body of the method and got a NameError, consider How can ...
In this case, there are some benefits to allowing this: 1) Methods are just functions that happen defined in a class, and need to be callable either as bound methods with implicit self passing or as plain functions with explicit self passing. 2) Making classmethod s and staticmethod s means you want to be able to rename and omit self respectively.
A self join is simply when you join a table with itself. There is no SELF JOIN keyword, you just write an ordinary join where both tables involved in the join are the same table. One thing to notice is that when you are self joining it is necessary to use an alias for the table otherwise the table name would be ambiguous. It is useful when you want to correlate pairs of rows from the same ...
17 What is self? In Python, every normal method is forced to accept a parameter commonly named self. This is an instance of class - an object. This is how Python methods interact with a class's state. You are allowed to rename this parameter whatever you please. but it will always have the same value:
Say I want to implement a method that pretty prints the struct to stdout, should I take &self? I guess self also works? As you can see, this is exactly a case for &self. If you use self (or &mut self) the method will likely still compile, but it can only be used in more restricted situations.
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Why is cls sometimes used instead of self as an argument in Python classes? For example: class Person: def __init__(self, firstname, lastname): self.firstname = firstname self.
Everyone is aware of this in javascript, but there are also instances of self encountered in the wild, such as here So, what is the difference between this and self in JavaScript?
