Classification with Python
In this notebook we try to practice all the classification algorithms that we learned in this course.
We load a dataset using Pandas library, and apply the following algorithms, and find the best one for this specific dataset by accuracy evaluation methods.
Lets first load required libraries:
import itertools
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.ticker import NullFormatter
import pandas as pd
import numpy as np
import matplotlib.ticker as ticker
from sklearn import preprocessing
%matplotlib inline
About dataset¶
This dataset is about past loans. The Loan_train.csv data set includes details of 346 customers whose loan are already paid off or defaulted. It includes following fields:
| Field | Description |
|---|---|
| Loan_status | Whether a loan is paid off on in collection |
| Principal | Basic principal loan amount at the |
| Terms | Origination terms which can be weekly (7 days), biweekly, and monthly payoff schedule |
| Effective_date | When the loan got originated and took effects |
| Due_date | Since it’s one-time payoff schedule, each loan has one single due date |
| Age | Age of applicant |
| Education | Education of applicant |
| Gender | The gender of applicant |
Lets download the dataset
!wget -O loan_train.csv https://s3-api.us-geo.objectstorage.softlayer.net/cf-courses-data/CognitiveClass/ML0101ENv3/labs/loan_train.csv
Load Data From CSV File¶
df = pd.read_csv('loan_train.csv')
df.head()
df.shape
Convert to date time object¶
df['due_date'] = pd.to_datetime(df['due_date'])
df['effective_date'] = pd.to_datetime(df['effective_date'])
df.head()
Data visualization and pre-processing¶
Let’s see how many of each class is in our data set
df['loan_status'].value_counts()
260 people have paid off the loan on time while 86 have gone into collection
Lets plot some columns to underestand data better:
# notice: installing seaborn might takes a few minutes
!conda install -c anaconda seaborn -y
import seaborn as sns
bins = np.linspace(df.Principal.min(), df.Principal.max(), 10)
g = sns.FacetGrid(df, col="Gender", hue="loan_status", palette="Set1", col_wrap=2)
g.map(plt.hist, 'Principal', bins=bins, ec="k")
g.axes[-1].legend()
plt.show()
bins = np.linspace(df.age.min(), df.age.max(), 10)
g = sns.FacetGrid(df, col="Gender", hue="loan_status", palette="Set1", col_wrap=2)
g.map(plt.hist, 'age', bins=bins, ec="k")
g.axes[-1].legend()
plt.show()
Pre-processing: Feature selection/extraction¶
Lets look at the day of the week people get the loan¶
df['dayofweek'] = df['effective_date'].dt.dayofweek
bins = np.linspace(df.dayofweek.min(), df.dayofweek.max(), 10)
g = sns.FacetGrid(df, col="Gender", hue="loan_status", palette="Set1", col_wrap=2)
g.map(plt.hist, 'dayofweek', bins=bins, ec="k")
g.axes[-1].legend()
plt.show()
We see that people who get the loan at the end of the week dont pay it off, so lets use Feature binarization to set a threshold values less then day 4
df['weekend'] = df['dayofweek'].apply(lambda x: 1 if (x>3) else 0)
df.head()
Convert Categorical features to numerical values¶
Lets look at gender:
df.groupby(['Gender'])['loan_status'].value_counts(normalize=True)
86 % of female pay their loans while only 73 % of males pay their loan
Lets convert male to 0 and female to 1:
df['Gender'].replace(to_replace=['male','female'], value=[0,1],inplace=True)
df.head()
df.groupby(['education'])['loan_status'].value_counts(normalize=True)
Feature befor One Hot Encoding¶
df[['Principal','terms','age','Gender','education']].head()
Use one hot encoding technique to conver categorical varables to binary variables and append them to the feature Data Frame¶
Feature = df[['Principal','terms','age','Gender','weekend']]
Feature = pd.concat([Feature,pd.get_dummies(df['education'])], axis=1)
Feature.drop(['Master or Above'], axis = 1,inplace=True)
Feature.head()
Feature selection¶
Lets defind feature sets, X:
X = Feature
X[0:5]
What are our lables?
y = df['loan_status'].values
y[0:5]
Normalize Data¶
Data Standardization give data zero mean and unit variance (technically should be done after train test split )
X= preprocessing.StandardScaler().fit(X).transform(X)
X[0:5]
Classification¶
Now, it is your turn, use the training set to build an accurate model. Then use the test set to report the accuracy of the model You should use the following algorithm:
- K Nearest Neighbor(KNN)
- Decision Tree
- Support Vector Machine
- Logistic Regression
Notice:
- You can go above and change the pre-processing, feature selection, feature-extraction, and so on, to make a better model.
- You should use either scikit-learn, Scipy or Numpy libraries for developing the classification algorithms.
- You should include the code of the algorithm in the following cells.
K Nearest Neighbor(KNN)¶
Notice: You should find the best k to build the model with the best accuracy.
warning: You should not use the loan_test.csv for finding the best k, however, you can split your train_loan.csv into train and test to find the best k.
# split train_loan
from sklearn.model_selection import train_test_split
X_train, X_test, y_train, y_test = train_test_split( X, y, test_size=0.2, random_state=4 )
print ('Train set:', X_train.shape, y_train.shape)
print ('Test set:', X_test.shape, y_test.shape)
# import library
from sklearn.neighbors import KNeighborsClassifier
from sklearn import metrics
# try with 10 different values of k to find the best one
Ks = 10
mean_acc = np.zeros((Ks-1))
std_acc = np.zeros((Ks-1))
ConfustionMx = [];
for n in range(1,Ks):
#Train Model and Predict
neigh = KNeighborsClassifier(n_neighbors = n).fit(X_train,y_train)
yhat=neigh.predict(X_test)
mean_acc[n-1] = metrics.accuracy_score(y_test, yhat)
std_acc[n-1]=np.std(yhat==y_test)/np.sqrt(yhat.shape[0])
# accuracy
print(mean_acc)
# Plot model accuracy for Different number of Neighbors
plt.plot(range(1,Ks),mean_acc,'g')
plt.fill_between(range(1,Ks),mean_acc - 1 * std_acc,mean_acc + 1 * std_acc, alpha=0.10)
plt.legend(('Accuracy ', '+/- 3xstd'))
plt.ylabel('Accuracy ')
plt.xlabel('Number of Nabors (K)')
plt.tight_layout()
plt.show()
# result
print( "The best accuracy was with", mean_acc.max(), "with k=", mean_acc.argmax()+1 )
# train model with k=7
neigh = KNeighborsClassifier(n_neighbors = 7).fit(X_train,y_train)
neigh
Decision Tree¶
# import library
from sklearn.tree import DecisionTreeClassifier
# create an instance of the DecisionTreeClassifier called loanTree
loanTree = DecisionTreeClassifier(criterion="entropy", max_depth = 4)
# training
loanTree.fit(X_train,y_train)
loanTree
Support Vector Machine¶
# import library
from sklearn import svm
# training
clf = svm.SVC()
clf.fit(X_train, y_train)
Logistic Regression¶
# import library
from sklearn.linear_model import LogisticRegression
# training
LR = LogisticRegression(C=0.01).fit(X_train,y_train)
LR
Model Evaluation using Test set¶
from sklearn.metrics import jaccard_similarity_score
from sklearn.metrics import f1_score
from sklearn.metrics import log_loss
First, download and load the test set:
!wget -O loan_test.csv https://s3-api.us-geo.objectstorage.softlayer.net/cf-courses-data/CognitiveClass/ML0101ENv3/labs/loan_test.csv
Load Test set for evaluation¶
test_df = pd.read_csv('loan_test.csv')
test_df.head()
# Pre-processing loan_test
test_df['due_date'] = pd.to_datetime(test_df['due_date'])
test_df['effective_date'] = pd.to_datetime(test_df['effective_date'])
test_df['dayofweek'] = df['effective_date'].dt.dayofweek
test_df['weekend'] = test_df['dayofweek'].apply(lambda x: 1 if (x>3) else 0)
test_df['Gender'].replace(to_replace=['male','female'], value=[0,1],inplace=True)
Feature_test = test_df[['Principal','terms','age','Gender','weekend']]
Feature_test = pd.concat([Feature_test,pd.get_dummies(test_df['education'])], axis=1)
Feature_test.drop(['Master or Above'], axis = 1,inplace=True)
test_X = Feature_test
test_X = preprocessing.StandardScaler().fit(test_X).transform(test_X)
test_X[0:5]
# Pre-processing loan_test (cont)
test_y = test_df['loan_status'].values
test_y[0:5]
KNN¶
# predicted y
yhat_knn = neigh.predict(test_X)
# jaccard
jaccard_knn = jaccard_similarity_score(test_y, yhat_knn)
print("KNN Jaccard index: ", jaccard_knn)
# f1_score
f1_score_knn = f1_score(test_y, yhat_knn, average='weighted')
print("KNN F1-score: ", f1_score_knn)
Decision tree¶
# predicted y
yhat_dt = loanTree.predict(test_X)
# jaccard
jaccard_dt = jaccard_similarity_score(test_y, yhat_dt)
print("DT Jaccard index: ", jaccard_dt)
# f1_score
f1_score_dt = f1_score(test_y, yhat_dt, average='weighted')
print("DT F1-score: ", f1_score_dt)
SVM¶
# predicted y
yhat_svm = clf.predict(test_X)
# jaccard
jaccard_svm = jaccard_similarity_score(test_y, yhat_svm)
print("SVM Jaccard index: ", jaccard_svm)
# f1_score
f1_score_svm = f1_score(test_y, yhat_svm, average='weighted')
print("SVM F1-score: ", f1_score_svm)
Logistic regression¶
# predicted y
yhat_lg = LR.predict(test_X)
yhat_lg_prob = LR.predict_proba(test_X)
# jaccard
jaccard_lg = jaccard_similarity_score(test_y, yhat_lg)
print("LR Jaccard index: ", jaccard_lg)
# f1_score
f1_score_lg = f1_score(test_y, yhat_lg, average='weighted')
print("LR F1-score: ", f1_score_lg)
# logloss
logloss_lg = log_loss(test_y, yhat_lg_prob)
print("LR log loss: ", logloss_lg)
Report¶
You should be able to report the accuracy of the built model using different evaluation metrics:
| Algorithm | Jaccard | F1-score | LogLoss |
|---|---|---|---|
| KNN | 0.6852 | 0.64538 | NA |
| Decision Tree | 0.5185 | 0.53858 | NA |
| SVM | 0.8148 | 0.7862 | NA |
| LogisticRegression | 0.740741 | 0.630418 | 0.60379 |
Want to learn more?
IBM SPSS Modeler is a comprehensive analytics platform that has many machine learning algorithms. It has been designed to bring predictive intelligence to decisions made by individuals, by groups, by systems – by your enterprise as a whole. A free trial is available through this course, available here: SPSS Modeler
Also, you can use Watson Studio to run these notebooks faster with bigger datasets. Watson Studio is IBM's leading cloud solution for data scientists, built by data scientists. With Jupyter notebooks, RStudio, Apache Spark and popular libraries pre-packaged in the cloud, Watson Studio enables data scientists to collaborate on their projects without having to install anything. Join the fast-growing community of Watson Studio users today with a free account at Watson Studio
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Author: Saeed Aghabozorgi
Saeed Aghabozorgi, PhD is a Data Scientist in IBM with a track record of developing enterprise level applications that substantially increases clients’ ability to turn data into actionable knowledge. He is a researcher in data mining field and expert in developing advanced analytic methods like machine learning and statistical modelling on large datasets.
Copyright © 2018 Cognitive Class. This notebook and its source code are released under the terms of the MIT License.