In this lesson, you’ll simulate a pointer in Python using object-oriented programming principles. You’ll create a class to track metrics for an application. You’ll use the @property decorator to access two counter values as if they were attributes.
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Simulated Pointers With Classes
00:00
In this video, I’ll show you how you can take advantage of object-oriented principles to mimic pointer behavior. What we want to do is create a Metrics class that will contain two counters: one for counting the number of function calls and another for counting the number of cat pictures served.
00:21
We’ll call methods in this class to increase these counters individually. First, let’s define the class. I’ll give it an __init__ method and create a dictionary to store both counters.
00:38 The dictionary type is mutable, so we can modify these counters without creating new dictionary objects. I will define two methods that can be used to get the values of the counters.
00:51
I’ll use the @property decorator so we can access this data as if it were an attribute. Now we just need a way to increment the counters. I’ll create two methods to do that, hardcoding in a += 1 so that neither counter can ever increase by more than 1 at a time.
01:13
All that’s left to do now is instantiate the class and try it out. To do that, I’ll create a name called metrics and point it to a new Metrics object.
01:25
Then I’ll call inc_cat_pictures() twice and inc_func_calls() once. Finally, I’ll print out the values of both counters using the properties.
01:40 Great! It looks like the counters worked. These methods of simulating pointers have worked all right, but they’re kind of, well, pointless, if you really think about it.
01:52 One of the biggest benefits of pointers is reduced memory usage or, at least, manual control over the memory you’re using. Python doesn’t let us do that.
02:03 Instead, we have to rely on the mutability of object types just to even mimic pointer behavior. Python is a high-level scripting language. If the code you’re writing requires pointer-level memory management, then Python might not be the right choice of language, at least not for that part of your codebase.
02:24 In the next and final lesson, I’ll show you where Python really shines: when you can interface it with C.
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