credit card fraud detection.

Code : Importing all the necessary Libraries

import the necessary packages

import numpy as np import pandas as pd import matplotlib.pyplot as plt import seaborn as sns from matplotlib import gridspec

Code : Loading the Data

Load the dataset from the csv file using pandas

best way is to mount the drive on colab and

copy the path for the csv file

data = pd.read_csv("credit.csv")

Code : Understanding the Data

Grab a peek at the data

data.head() Code : Describing the Data

Print the shape of the data

data = data.sample(frac = 0.1, random_state = 48) print(data.shape) print(data.describe())

Code : Imbalance in the data Time to explain the data we are dealing with.

Determine number of fraud cases in dataset

fraud = data[data['Class'] == 1] valid = data[data['Class'] == 0] outlierFraction = len(fraud)/float(len(valid)) print(outlierFraction) print('Fraud Cases: {}'.format(len(data[data['Class'] == 1]))) print('Valid Transactions: {}'.format(len(data[data['Class'] == 0])))

Lets first apply our models without balancing it and if we don’t get a good accuracy then we can find a way to balance this dataset. But first, let’s implement the model without it and will balance the data only if needed.

Code : Print the amount details for Fraudulent Transaction

print(“Amount details of the fraudulent transaction”) fraud.Amount.describe()

Code : Print the amount details for Normal Transaction

print(“details of valid transaction”) valid.Amount.describe()

Code : Plotting the Correlation Matrix The correlation matrix graphically gives us an idea of how features correlate with each other and can help us predict what are the features that are most relevant for the prediction.

Correlation matrix

corrmat = data.corr() fig = plt.figure(figsize = (12, 9)) sns.heatmap(corrmat, vmax = .8, square = True) plt.show()

Code : Separating the X and the Y values Dividing the data into inputs parameters and outputs value format

dividing the X and the Y from the dataset

X = data.drop(['Class'], axis = 1) Y = data["Class"] print(X.shape) print(Y.shape)

getting just the values for the sake of processing

(its a numpy array with no columns)

xData = X.values yData = Y.values

Training and Testing Data Bifurcation We will be dividing the dataset into two main groups. One for training the model and the other for Testing our trained model’s performance.

Using Skicit-learn to split data into training and testing sets

from sklearn.model_selection import train_test_split

Split the data into training and testing sets

xTrain, xTest, yTrain, yTest = train_test_split( xData, yData, test_size = 0.2, random_state = 42)

Code : Building a Random Forest Model using skicit learn

Building the Random Forest Classifier (RANDOM FOREST)

from sklearn.ensemble import RandomForestClassifier

random forest model creation

rfc = RandomForestClassifier() rfc.fit(xTrain, yTrain)

predictions

yPred = rfc.predict(xTest)

Code : Building all kinds of evaluating parameters

Evaluating the classifier

printing every score of the classifier

scoring in anything

from sklearn.metrics import classification_report, accuracy_score
from sklearn.metrics import precision_score, recall_score from sklearn.metrics import f1_score, matthews_corrcoef from sklearn.metrics import confusion_matrix

n_outliers = len(fraud) n_errors = (yPred != yTest).sum() print("The model used is Random Forest classifier")

acc = accuracy_score(yTest, yPred) print("The accuracy is {}".format(acc))

prec = precision_score(yTest, yPred) print("The precision is {}".format(prec))

rec = recall_score(yTest, yPred) print("The recall is {}".format(rec))

f1 = f1_score(yTest, yPred) print("The F1-Score is {}".format(f1))

MCC = matthews_corrcoef(yTest, yPred) print("The Matthews correlation coefficient is{}".format(MCC))

Code : Visulalizing the Confusion Matrix

printing the confusion matrix

LABELS = ['Normal', 'Fraud'] conf_matrix = confusion_matrix(yTest, yPred) plt.figure(figsize =(12, 12)) sns.heatmap(conf_matrix, xticklabels = LABELS,
yticklabels = LABELS, annot = True, fmt ="d"); plt.title("Confusion matrix") plt.ylabel('True class') plt.xlabel('Predicted class') plt.show()