matplotlib: Plot Feature Importance with feature names
Quick answer for data scientists that ain't got no time to waste:
Load the feature importances into a pandas series indexed by your column names, then use its plot method. For a classifier model
trained using X
:
feat_importances = pd.Series(model.feature_importances_, index=X.columns)
feat_importances.nlargest(20).plot(kind='barh')
Slightly more detailed answer with a full example:
Assuming you trained your model with data contained in a pandas dataframe, this is fairly painless if you load the feature importance into a panda's series, then you can leverage its indexing to get the variable names displayed easily. The plot argument kind='barh'
gives us a horizontal bar chart, but you could easily substitute this argument for kind='bar'
for a traditional bar chart with the feature names along the x-axis if you prefer.
nlargest(n)
is a pandas Series method which will return a subset of the series with the largest n
values. This is useful if you've got lots of features in your model and you only want to plot the most important.
A quick complete example using the classic Kaggle Titanic dataset...
import pandas as pd
from sklearn.ensemble import RandomForestClassifier
%matplotlib inline # don't forget this if you're using jupyter!
X = pd.read_csv("titanic_train.csv")
X = X[['Pclass', 'Age', 'Fare', 'Parch', 'SibSp', 'Survived']].dropna()
y = X.pop('Survived')
model = RandomForestClassifier()
model.fit(X, y)
(pd.Series(model.feature_importances_, index=X.columns)
.nlargest(4)
.plot(kind='barh')) # some method chaining, because it's sexy!
Which will give you this:
Not exactly sure what you are looking for. Derived a example from here. As mentioned in the comment: you can change indices
to a list of labels at line plt.yticks(range(X.shape[1]), indices)
if you want to customize feature labels.
import numpy as np
import matplotlib.pyplot as plt
from sklearn.datasets import make_classification
from sklearn.ensemble import ExtraTreesClassifier
# Build a classification task using 3 informative features
X, y = make_classification(n_samples=1000,
n_features=10,
n_informative=3,
n_redundant=0,
n_repeated=0,
n_classes=2,
random_state=0,
shuffle=False)
# Build a forest and compute the feature importances
forest = ExtraTreesClassifier(n_estimators=250,
random_state=0)
forest.fit(X, y)
importances = forest.feature_importances_
std = np.std([tree.feature_importances_ for tree in forest.estimators_],
axis=0)
indices = np.argsort(importances)
# Plot the feature importances of the forest
plt.figure()
plt.title("Feature importances")
plt.barh(range(X.shape[1]), importances[indices],
color="r", xerr=std[indices], align="center")
# If you want to define your own labels,
# change indices to a list of labels on the following line.
plt.yticks(range(X.shape[1]), indices)
plt.ylim([-1, X.shape[1]])
plt.show()
It's possible to just pass df.columns
as the parameter for plt.xticks()
,i have written a sample implementation.
plt.bar( range(len(model.feature_importances_)), model.feature_importances_)
plt.xticks(range(len(model.feature_importances_)), train_features.columns)
plt.show()