Comments (4)
Thanks again for reporting this @tomicapretto . This should be resolved as of 0.6.5+.
from formulaic.
Hi @tomicapretto ,
Thanks for taking the time to report this. However, this is actually expected behaviour due to the ordered nature of formulae and the automatic full-rank algorithm (where terms to the left take precedence over terms to the right in terms of materialization).
That is:
>>> print(model_matrix("0 + g + 1", df))
g[T.a] g[T.b]
0 1 0
1 1 0
2 1 0
3 0 1
4 0 1
>>> print(model_matrix("0 + 1 + g", df))
Intercept g[T.b]
0 1.0 0
1 1.0 0
2 1.0 0
3 1.0 1
4 1.0 1
These model matrices are equivalent, and the columns span the vector space (i.e. the model matrix is full rank). In both cases the intercept is spanned, but in the former case it is spanned by the categorical factors.
I'll close this one out for now, but let me know if have further questions!
from formulaic.
Hmm... but this does, upon further reflection, not match the behaviour expected by users of R or patsy. It might be worth special casing the full rank algorithm to deal with the intercept. Point taken. I'll fix this!
from formulaic.
@matthewwardrop your explanation makes perfect sense (i.e. terms to the left take precedence over terms to the right). But as you said, it may be surprising to users coming from Patsy or R. I don't have a strong preference. But if you decide to continue with the current approach, it would be good to leave a note in the documentation explaining why it works the way it works in this specific case. I could open a PR 😄
from formulaic.
Related Issues (20)
- How to include structural zeros? HOT 1
- Retain Column Names for sparse model matrices HOT 4
- Formulaic not raising an exception when required fields are missing in the dataset HOT 2
- Allow formatting the categorical encoded variables HOT 4
- Throw error when formula has parameters that are not available HOT 2
- Support polars HOT 4
- Dropping Indices via "+0" or "-1" and reference levels for categoricals HOT 1
- Extending `formulaic` to work with other input types HOT 2
- Handling individual columns that can expand into multiple columns HOT 7
- Support the hashing trick as an encoding strategy for categorical features HOT 6
- `model_spec.transform_state` bugged when formula is not correctly written HOT 1
- Is there a way to get the baseline value for categorical variables? HOT 7
- Add . operator HOT 1
- Suggestions for creating `get_feature_names_out` for Scikit Learn ColumnTransformer compatibility? HOT 3
- Is it possible to define custom operators? HOT 2
- Is it possible to force the `Formula` class to not expand categorical variables? HOT 3
- Add required variables to the `Formula` class HOT 6
- Potential Bug / different defaults for Intercept / Reference Levels when using `Formula.get_model_matrix()` with categoricals HOT 2
- Potential bug in Interacting variables via `:` syntax for categorical variables HOT 3
- Incompatibility with pandas development version HOT 2
Recommend Projects
-
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
-
Vue.js
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
-
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
-
TensorFlow
An Open Source Machine Learning Framework for Everyone
-
Django
The Web framework for perfectionists with deadlines.
-
Laravel
A PHP framework for web artisans
-
D3
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
-
Recommend Topics
-
javascript
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
-
web
Some thing interesting about web. New door for the world.
-
server
A server is a program made to process requests and deliver data to clients.
-
Machine learning
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
-
Visualization
Some thing interesting about visualization, use data art
-
Game
Some thing interesting about game, make everyone happy.
Recommend Org
-
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
-
Microsoft
Open source projects and samples from Microsoft.
-
Google
Google ❤️ Open Source for everyone.
-
Alibaba
Alibaba Open Source for everyone
-
D3
Data-Driven Documents codes.
-
Tencent
China tencent open source team.
from formulaic.