Randomized-Search

Sun 29 June 2025 
import pyutil as pyu

pyu.get_local_pyinfo()

'conda env: C:\\Users\\Afia Jahan\\anaconda3\\envs\\py312; pyv: 3.12.11 | packaged by Anaconda, Inc. | (main, Jun  5 2025, 12:58:53) [MSC v.1929 64 bit (AMD64)]'

import pandas as pd
from sklearn.ensemble import RandomForestClassifier
from sklearn.model_selection import train_test_split, RandomizedSearchCV
from sklearn.metrics import accuracy_score
from scipy.stats import randint

# Load the Titanic dataset
url = 'https://raw.githubusercontent.com/datasciencedojo/datasets/master/titanic.csv'
data = pd.read_csv(url)

# Preprocessing
# Select features and target
features = ['Pclass', 'Sex', 'Age', 'SibSp', 'Parch', 'Fare', 'Embarked']
X = data[features]
y = data['Survived']

# Handle missing values
X.loc[:, 'Age'] = X['Age'].fillna(X['Age'].median())
X.loc[:, 'Embarked'] = X['Embarked'].fillna(X['Embarked'].mode()[0])

# Convert categorical variables to numerical
X = pd.get_dummies(X, columns=['Sex', 'Embarked'], drop_first=True)

# Train-test split
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)

# Define the model
model = RandomForestClassifier(random_state=42)

# Define the hyperparameter distributions
param_distributions = {
    'n_estimators': randint(100, 500),       # Randomly choose from 100 to 500
    'max_depth': randint(5, 20),            # Randomly choose from 5 to 20
    'min_samples_split': randint(2, 10),    # Randomly choose from 2 to 10
}

# RandomizedSearchCV
random_search = RandomizedSearchCV(
    estimator=model,
    param_distributions=param_distributions,
    n_iter=50,       # Number of random combinations to try
    cv=5,            # 5-fold cross-validation
    scoring='accuracy',
    random_state=42,
    n_jobs=-1        # Use all available cores
)
random_search.fit(X_train, y_train)

RandomizedSearchCV(cv=5, estimator=RandomForestClassifier(random_state=42),
                   n_iter=50, n_jobs=-1,
                   param_distributions={'max_depth': <scipy.stats._distn_infrastructure.rv_discrete_frozen object at 0x00000173E76B6DE0>,
                                        'min_samples_split': <scipy.stats._distn_infrastructure.rv_discrete_frozen object at 0x00000173E79D85C0>,
                                        'n_estimators': <scipy.stats._distn_infrastructure.rv_discrete_frozen object at 0x00000173E768D610>},
                   random_state=42, scoring='accuracy')
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# Print best parameters and score
print("Best Parameters:", random_search.best_params_)
print("Best Score:", random_search.best_score_)

Best Parameters: {'max_depth': 7, 'min_samples_split': 2, 'n_estimators': 491}
Best Score: 0.8342263370432385

# Evaluate on the test set
best_model = random_search.best_estimator_
y_pred = best_model.predict(X_test)
print("Test Accuracy:", accuracy_score(y_test, y_pred))# Evaluate on the test set

Test Accuracy: 0.8156424581005587

Score: 10

Category: basics