How to duplicate an estimator in order to use it on multiple data sets?

Question

Here is an example that creates two data sets:

from sklearn.linear_model import LogisticRegression
from sklearn.datasets import make_classification

# data set 1
X1, y1 = make_classification(n_classes=2, n_features=5, random_state=1)
# data set 2
X2, y2 = make_classification(n_classes=2, n_features=5, random_state=2)

I want to use the LogisticRegression estimator with the same parameter values to fit a classifier on each data set:

lr = LogisticRegression()

clf1 = lr.fit(X1, y1)
clf2 = lr.fit(X2, y2)

print "Classifier for data set 1: "
print "  - intercept: ", clf1.intercept_
print "  - coef_: ", clf1.coef_

print "Classifier for data set 2: "
print "  - intercept: ", clf2.intercept_
print "  - coef_: ", clf2.coef_

The problem is that both classifiers are the same:

Classifier for data set 1: 
  - intercept:  [ 0.05191729]
  - coef_:  [[ 0.06704494  0.00137751 -0.12453698 -0.05999127  0.05798146]]
Classifier for data set 2: 
  - intercept:  [ 0.05191729]
  - coef_:  [[ 0.06704494  0.00137751 -0.12453698 -0.05999127  0.05798146]]

For this simple example, I could use something like:

lr1 = LogisticRegression()
lr2 = LogisticRegression()

clf1 = lr1.fit(X1, y1)
clf2 = lr2.fit(X2, y2)

to avoid the problem. However, the question remains: How to duplicate/copy an estimator with its particular parameter values in general?

Answer 1

from sklearn.linear_model import LogisticRegression

from sklearn.base import clone

lr1 = LogisticRegression()

lr2 = clone(lr1)

print(lr1)

print(lr2)