Python for Entrepreneurs Transcripts
Chapter: Appendix: Python language concepts
Lecture: Concept: objects vs. classes
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When you are new to object-oriented programming, the idea of classes and objects often can seem interchangeable
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and some people use them interchangeably; that's not really correct and so let's take just a moment and really clarify the relationship
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and differences between classes and objects. So here we have a Creature class, you can it has an initializer and a walk method,
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and notice that the walk method does something different if the creature is powerful, if its power is greater than 10 versus if it's lower.
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This class is a blueprint for creating creatures. We could create a squirrel, we could create a dragon,
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we could create a tiger, and those would all be specific objects or instances of the Creature class.
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So down here we’re going to create a squirrel and a dragon, and notice the squirrel is created with power 7, the dragon is created with power 50.
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Now these are both creatures, but they are now distinct things in memory.
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Objects are created via classes and the squirrel object is somewhere in memory
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and it has a power 7 and it has this walk behavior it gets from its class, but all of its variables are specific to it.
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We have also the dragon creature, with its own variables, so it's power is 50 and if we change its power, it won't change the squirrel
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or any other creature, just the dragon. And when we call squirrel.walk(), the squirrel is going to walk in some specific way based on its own power.
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So you can see the Creature class test is a power greater than 10 or less than 10 and if it's greater than 10, it does something special,
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maybe it walks in a powerful way versus a non-powerful way, who knows, but that will mean the squirrel walks in one way
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and the dragon walks in another way, even though they are both instances of the Creature class.
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So I hope that clears up the relationship between classes and objects.