DEV Community

Cover image for why is random state 42
ANNA LAPUSHNER
ANNA LAPUSHNER

Posted on

why is random state 42

I am loving working with AI assistants. They AI's are clear, helpful, transparent and delightfully culturally aware.

I asked a brilliant AI why the random state is set to 42 when executing k-means and imagine my delight when this was the answer!

That's a great question! Setting random_state=42 (or to any fixed number) in machine learning algorithms like KMeans serves a very specific purpose: reproducibility.

Image description

Why 42?
The number 42 is a popular choice in the data science community, often used as a placeholder or default value for random states. It has its origins in the science fiction comedy series "The Hitchhiker's Guide to the Galaxy" by Douglas Adams, where it is the "Answer to the Ultimate Question of Life, the Universe, and Everything". While it doesn't hold any special mathematical significance, it has become a somewhat humorous tradition.

Image description

Here's why it's important:
KMeans is Stochastic: The KMeans algorithm starts by randomly initializing the cluster centroids. This means that if you run the algorithm multiple times without fixing the random state, you might get slightly different results each time.
Consistent Results: By setting random_state to a fixed value, you ensure that the random number generator used within the algorithm is initialized in the same way every time. This leads to consistent results across multiple runs, making your experiments reproducible.

Image description

Debugging and Collaboration:
Reproducibility is crucial for debugging your code and sharing your work with others. If someone else runs your code with the same random state, they should get the exact same results.

Image description

Top comments (0)