setting self variables based on each other-CodePudding

quick question in python let's say my class goes like this

class Enemy():
   def __init__(self, level):
      self.level = level
      self.damage = self.level   5

the thing is that since the self.damage value is instantiated once it will not update when self.level is changed, how can I make it do just that? I tried searching online but I have no idea what this is called so I cannot find any help

CodePudding user response：

You can use properties. Maybe you know getter and setter methods from other programming languages. Properties are the Python equivalent of them. In this case, you only need a getter method.

class Enemy():
   def __init__(self, level):
      self.level = level

   @property
   def damage(self):
      return self.level   5

The beauty is, you can still access damage as an attribute on your instance like enemy.damage, without having to explicitly call the method, it's done automatically.

CodePudding user response：

In addition to using properties, you can also make damage a function rather than a variable:

def damage():
    return self.level   5

CodePudding user response：

This is a nice article about properties:
https://www.freecodecamp.org/news/python-property-decorator/

They allow you to control how attributes are accessed, which makes it easier to update them in the future if you decide a change in needed. For example, instead of being a flat 5, you can change the value or make it variable and anything that calls the attribute will not be affected.

Later you can add a way of manually setting the damage if you wanted to, through the use of @damage.setter.

class Enemy():
  '''This holds the data and functionality for enemies'''

  def __init__(self, level):
    self.level = level
    # Show the damage being set
    print(self.damage)

  @property
  def damage(self):
    return self.level   5