What is yahoo finance?.

Yahoo Finance data is through the yfinance library — a powerful, unofficial API wrapper that makes it easy to fetch financial data for analysis, modeling, or trading strategies.

yfinance is a Python package that allows you to:

• Download historical stock prices
• Access real-time market data
• Retrieve company financials, dividends, and splits
• Analyze stock actions and key statistics

1. Install yahoo finance library

pip install yfinance

Example: loading financial data from yahoo finance

import pandas as pd 
import yfinance as yf
start_date="2015-01-01"
end_date = "2025-06-30"

symbol="XYZ.NSE"
df=yf.download(symbol,start_date,end_date)
df
df.info()

What is pandas

Pandas is a powerful open-source Python library used for data manipulation and analysis. It’s built on top of NumPy and is especially well-suited for working with structured data like time series, tabular data (think Excel spreadsheets), and financial datasets — which makes it a favorite in the world of algorithmic trading.

How Pandas Helps in Algorithmic Trading

Pandas is practically the backbone of many algo trading systems. Here’s how it fits in:

1. Data Acquisition & Preprocessing

• Load historical stock data using APIs like yfinance or pandas-datareader
• Clean and format the data (e.g., handle missing values, convert timestamps)

2. Feature Engineering

• Calculate technical indicators like moving averages, RSI, MACD
• Create custom signals based on price patterns or volume

3. Strategy Development

• Use logical conditions to define buy/sell signals
• Combine multiple indicators to build complex strategies

4. Backtesting

• Simulate trades using historical data
• Calculate returns, drawdowns, Sharpe ratio, etc.

5. Visualization

• Plot price charts, indicators, and performance metrics using Matplotlib or Seaborn