Chapter 5Artificial Intelligence~1 min read
Scikit-learn — Classical ML
पहिले ML Model बनवा
Scikit-learn हे Python मधले most popular classical ML library आहे. Linear Regression, Decision Trees, SVM, K-Means — सगळे algorithms consistent API सोबत available आहेत. पहिला real ML model scikit-learn नेच बनवतात.
Complete ML example — House Price Prediction
python
import pandas as pd
import numpy as np
from sklearn.model_selection import train_test_split
from sklearn.preprocessing import StandardScaler
from sklearn.linear_model import LinearRegression
from sklearn.metrics import mean_squared_error, r2_score
# Data load करा
df = pd.read_csv('houses.csv')
X = df[['area', 'bedrooms', 'age']].values # features
y = df['price'].values # target
# Train/Test split — 80% train, 20% test
X_train, X_test, y_train, y_test = train_test_split(
X, y, test_size=0.2, random_state=42
)
# Feature Scaling — important for many algorithms
scaler = StandardScaler()
X_train = scaler.fit_transform(X_train)
X_test = scaler.transform(X_test) # Note: transform only, not fit!
# Model train करा
model = LinearRegression()
model.fit(X_train, y_train)
# Predictions
y_pred = model.predict(X_test)
# Evaluate
rmse = np.sqrt(mean_squared_error(y_test, y_pred))
r2 = r2_score(y_test, y_pred)
print(f"RMSE: {rmse:.2f}")
print(f"R² Score: {r2:.3f}") # 1.0 = perfectClassification Example — Spam Detection
Logistic Regression classifier
python
from sklearn.linear_model import LogisticRegression
from sklearn.metrics import accuracy_score, classification_report
# Same split/scale steps...
clf = LogisticRegression()
clf.fit(X_train, y_train)
y_pred = clf.predict(X_test)
print(f"Accuracy: {accuracy_score(y_test, y_pred):.2%}")
print(classification_report(y_test, y_pred))
# Precision, Recall, F1 score दाखवतोCommon Algorithms
- ▸Linear Regression — continuous value predict (house prices)
- ▸Logistic Regression — binary classification (spam/not spam)
- ▸Decision Tree — interpretable, tree-based decisions
- ▸Random Forest — multiple decision trees, more accurate
- ▸SVM (Support Vector Machine) — powerful classifier
- ▸K-Means — clustering, customer segmentation
- ▸KNN (K-Nearest Neighbors) — simple, instance-based
✅ Key Points — लक्षात ठेवा
- ▸train_test_split — model evaluate करायला
- ▸StandardScaler — features same scale वर आणा
- ▸fit() — model train, predict() — predictions
- ▸Accuracy: classification, RMSE/R²: regression
- ▸Random Forest: Decision Tree पेक्षा almost always better
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