scikit-playtime

Rethinking machine learning pipelines a bit.

What does scikit-playtime do?

I was wondering if there might be an easier way to construct scikit-learn pipelines. Don't get me wrong, scikit-learn is amazing when you want elaborate pipelines (exibit A, exibit B) but maybe there is also a place for something more lightweight and playful. This library is all about exploring that.

Imagine that you are dealing with the titanic dataset.

import pandas as pd 

df = pd.read_csv("https://calmcode.io/static/data/titanic.csv")
df.head()

Here's what the dataset looks like.

survived	pclass	name	sex	age	fare	sibsp	parch
0	3	Braund, Mr. Owen Harris	male	22	7.25	1	0
1	1	Cumings, Mrs. John Bradley (Florence Briggs Thayer)	female	38	71.2833	1	0
1	3	Heikkinen, Miss. Laina	female	26	7.925	0	0
1	1	Futrelle, Mrs. Jacques Heath (Lily May Peel)	female	35	53.1	1	0
0	3	Allen, Mr. William Henry	male	35	8.05	0	0

The goal of this dataset is to predict who survived, so survived is the target column for a classification task. But in order to make the right predictions you would need to encode the features in the right way. So to do that, you might construct a preprocessing pipeline like this:

from sklearn.pipeline import make_union, make_pipeline
from sklearn.preprocessing import OneHotEncoder
from skrub import SelectCols

pipe = make_union(
    SelectCols(["age", "fare", "sibsp", "parch"]),
    make_pipeline(
        SelectCols(["sex", "pclass"]),
        OneHotEncoder()
    )
)

This pipeline takes the age, fare, sibsp and parch features as-is. These features are already numeric so these do not need to be changed. But the sex and pclass features are candidates to one-hot encode first. These are categorical features, so it helps to encode them as such.

The pipeline works, and it's fine, but you could wonder if this is easy. After all, you do need to know scikit-learn fairly well in order to build a pipeline this way and you may also need to appreciate Python. There's some nesting happening in here as well, so for a novice or somebody who just immediately wants to make a quick model ... there's some stuff that gets in the way. All of this is fine when you consider that scikit-learn needs to allow for elaborate pipelines ... but if you just want something dead simple ... then you may appreciate another syntax instead.

Enter playtime.

Playtime offers an API that allows you to declare the aforementioned pipeline by doing this instead:

from playtime.formula import feats, onehot

formula = feats("age", "fare", "sibsp", "parch") + onehot("sex", "pclass")

This forumla object is just an object that can accumulate components and you can access the generated pipeline by checking the .pipeline property.

formula.pipeline

It's pretty much the same pipeline, but it's a lot easier to go ahead and declare. You're mostly dealing with column names and how to encode them, instead of thinking about how scikit-learn constructs a pipeline.

This is what scikit-playtime is all about, but this is just the start of what it can do. If that sounds interest you can read more on the documentation page.

Alternative you may also explore this tool by installing it via:

python -m pip install scikit-playtime

Thanks

This project was originally part of my work over at calmcode labs but my employer probabl has been very supportive and has allowed me to work on this project during my working hours. This was super cool and I wanted to make sure I recognise them for it.