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Python Init Function Example, Syntax & Best Practices

In this article, we will take a look at the Python Init Function using an example. At first, we learn about it’s syntax and how we can use it. But once we are comfortable with it, we will then learn the best practices to use when we want to call it!

So, does this plan sound good? Yes? Then let’s do it! 😉

Python Init Function Example and its syntax
Python Init Function Example and its syntax explained in 5 minutes

What Is The Syntax Of Python Init Function?

So first, let us start with how the syntax of a Python Init function looks like. Now, for us to know about it, we will have to take a look at the Python’s official document. From this, we now get to know that the init function is a method of a class and it looks like:

def __init__(self)

From the above code, we can see that the init function takes at least one argument. This is called as ‘self‘ and it has got a special meaning to it. But before we learn about it, let us first know how Python’s Class works.

You see, in Python a Class can have many methods in it. But it will have one method in it for sure. It is called the init() method. Now this method will be present in a Python Class even if you have not declared it yourself!

So, in other words, init() is a function that you will always find in any Class of Python. If you declared it yourself, it is an explicit init() function. But if you did not, it will be an implicit init() function!

Alright, so we now that an init() function is always present in any Python Class, what does it do? We will answer this question next!

Why do we need an init() function in Python?

So to answer this, we need you to have some knowledge about Object Oriented Programming (OOP). So if you are not so familiar with it, please go and learn about constructors in OOP. But for now, I will assume that you do know about OOP.

So as you know in OOP, we have a constructor method in every Class. So whenever we create an object using a Class, its constructor method will get called. Right?

In the same way, in Python the init function acts as a constructor. So it will get called whenever we create a Python’s Class object.

So this is why I said that the init() function is always present in a Python Class. So, the syntax of the init() that you saw above is how it looks like when it is implicit.

What does the self parameter do?

In order to answer this, let us take a look at the syntax once again

class Test:
    def __init__(self)

Here, we are looking at the code of an example Python class called Test. So here we can see that the init function has one argument called self.

Now, in order to for us to understand what this self argument does, let us first create an object of the Test class type.

t = Test()

So in the above code, we created a new object instance of the Test class. Now, as soon as this code runs, the init() function of the Test class will get called. But what is getting passed as the self argument here the variable t itself.

So, we now see that the self argument of the init() function points to the instance of the object itself!

Are you clear until now? Good! Then let us now look into an example of Python Init() function.

Python Init Function Example

So, let us take a look at this Python Init function example code

class Point:
    def __init__(self, x, y):
        _x = x
        _y = y

p = Point(1,2)

From the above code, we can see that we now have a new Class called Point. We also have an init() function that we have defined explicitly. This init() function takes in three arguments self, x & y.

Is it all clear? Good!

So we can quickly see the advantage of using init() function here. With the help of this function, we are able to set the initial values of x & y variables!

So when we created an instance of Point class using the code:

p = Point(1,2)

we were able to set the p object’s x & y values to 1 & 2 right away!

So, if things are clear until this point, we will then move on to the last part of this article.

Best Practices With Python Init Function

So here is a list of best practices you should follow when writing an init function:

  • Always use Init() function to initialize values to object parameters
  • Reduce the number of parameters passed to the init() if possible. Do not over use it.
  • Keep the init() function simple. Do not abuse it!

Conclusion

So that is about it! That is all you need to know about Python init() function. We have discussed everything there is to know about Python’s init() function with an example. We also went through the best practice we should follow when making use of it.

So with this, I will end this article here. If you still have any more questions, please ask it in the comment section below!

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So until next time, have a nice day! 🙂

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