Release highlights for 1.3

doc/whats_new/v1.3.rst

@@ -9,6 +9,9 @@ Version 1.3.0
 
 **In Development**
 
+For a short description of the main highlights of the release, please refer to
+:ref:`sphx_glr_auto_examples_release_highlights_plot_release_highlights_1_3_0.py`.
+
 .. include:: changelog_legend.inc
 
 Changed models

examples/release_highlights/plot_release_highlights_1_3_0.py

@@ -0,0 +1,99 @@
+# flake8: noqa
+"""
+=======================================
+Release Highlights for scikit-learn 1.3
+=======================================
+
+.. currentmodule:: sklearn
+
+We are pleased to announce the release of scikit-learn 1.3! Many bug fixes
+and improvements were added, as well as some new key features. We detail
+below a few of the major features of this release. **For an exhaustive list of
+all the changes**, please refer to the :ref:`release notes <changes_1_3>`.
+
+To install the latest version (with pip)::
+
+    pip install --upgrade scikit-learn
+
+or with conda::
+
+    conda install -c conda-forge scikit-learn
+
+"""
+
+# %%
+# HDBSCAN: hierarchical density-based clustering
+# ----------------------------------------------
+# Originally hosted in the scikit-learn-contrib repository, :class:`cluster.HDBSCAN`
+# has been adpoted into scikit-learn. It's missing a few features from the original
+# implementation which will be added in future releases.
+# By performing :class:`cluster.DBSCAN` over varying epsilon values
+# :class:`cluster.HDBSCAN` finds clusters of varying densities making it more robust to
+# parameter selection than :class:`cluster.DBSCAN`. More details in the
+# :ref:`User Guide <hdbscan>`.
+import numpy as np
+from sklearn.cluster import HDBSCAN
+from sklearn.datasets import load_digits
+from sklearn.metrics import v_measure_score
+
+X, true_labels = load_digits(return_X_y=True)
+print(f"number of digits: {len(np.unique(true_labels))}")
+
+hdbscan = HDBSCAN(min_cluster_size=15).fit(X)
+non_noisy_labels = hdbscan.labels_[hdbscan.labels_ != -1]
+print(f"number of clusters found: {len(np.unique(non_noisy_labels))}")
+
+v_measure_score(true_labels[hdbscan.labels_ != -1], non_noisy_labels)
+
+# %%
+# TargetEncoder: a new category encoding strategy
+# -----------------------------------------------
+# Well suited for categorical features with high cardinality,
+# :class:`preprocessing.TargetEncoder` encodes the categories based on a shrunk
+# estimate of the average target values for observations belonging to that category.
+# More details in the :ref:`User Guide <target_encoder>`.
+import numpy as np
+from sklearn.preprocessing import TargetEncoder
+
+X = np.array([["cat"] * 30 + ["dog"] * 20 + ["snake"] * 38], dtype=object).T
+y = [90.3] * 30 + [20.4] * 20 + [21.2] * 38
+
+enc = TargetEncoder(random_state=0)
+X_trans = enc.fit_transform(X, y)
+
+enc.encodings_
+
+# %%
+# Missing values support in decision trees
+# ----------------------------------------
+# The classes :class:`tree.DecisionTreeClassifier` and
+# :class:`tree.DecisionTreeRegressor` now support missing values. For each potential
+# threshold on the non-missing data, the splitter will evaluate the split with all the
+# missing values going to the left node or the right node.
+# More details in the :ref:`User Guide <tree_missing_value_support>`.
+import numpy as np
+from sklearn.tree import DecisionTreeClassifier
+
+X = np.array([0, 1, 6, np.nan]).reshape(-1, 1)
+y = [0, 0, 1, 1]
+
+tree = DecisionTreeClassifier(random_state=0).fit(X, y)
+tree.predict(X)
+
+# %%
+# Metadata Routing
+# ----------------
+# We are in the process of introducing a new way to route metadata such as
+# ``sample_weight`` throughout the codebase, which would affect how
+# meta-estimators such as :class:`pipeline.Pipeline` and
+# :class:`model_selection.GridSearchCV` route metadata. While the
+# infrastructure for this feature is already included in this release, the work
+# is ongoing and not all meta-estimators support this new feature. You can read
+# more about this feature in the :ref:`Metadata Routing User Guide
+# <metadata_routing>`. Note that this feature is still under development and
+# not implemented for most meta-estimators.
+#
+# Third party developers can already start incorporating this into their
+# meta-estimators. For more details, see
+# :ref:`metadata routing developer guide
+# <sphx_glr_auto_examples_miscellaneous_plot_metadata_routing.py>`.