A simple way to have many class constructors in Python

Photo by Iker Urteaga on Unsplash

Something missing in Python, which you may be envious of if you are coming from programming languages like C++ or Crystal, is the ability to overload a function or method, especially a class constructor which is the focus of this article. I will show you a simple and elegant way to overcome this issue and avoid a pitfall I see in some code around.

For our example, we will consider a simple Point class that will be a representation of a vector in two dimensions. It can be instantiated in three different ways:

• Pass the two coordinates x and y directly
• Pass an array of values
• Pass a dict (or map in C++ jargon)

Here is what it can look at in C++. Honestly, my C++ is rusty, so I asked ChatGPT to help me with this part. 🫣

#include <iostream>
#include <vector>
#include <map>
using namespace std;

class Point {
   private:
    int x;
    int y;

   public:
    // Constructor with two separate parameters for x and y
    Point(int x, int y) {
        this->x = x;
        this->y = y;
    }

    // Constructor with a vector having x and y
    Point(vector<int> vec) {
        if (vec.size() != 2) {
            throw invalid_argument("The vector should have only two elements represeting x and y coordinates.");
        }
        x =…