Common Window Functions:

• .mean() - Average within window
• .sum() - Sum within window
• .std() - Standard deviation
• .var() - Variance
• .min() / .max() - Minimum/Maximum
• .median() - Median value
• .quantile() - Quantile calculation
• .apply() - Custom function
• .corr() - Correlation
• .cov() - Covariance

Shift Operations:

• .shift(n) - Lag by n periods (positive n)
• .shift(-n) - Lead by n periods (negative n)
• .diff() - First difference
• .pct_change() - Percentage change

Ranking Functions:

• .rank() - Assign ranks
• method='average' - Average rank for ties
• method='min' - Minimum rank for ties
• method='dense' - Dense ranking
• pct=True - Percentile ranks
• ascending=False - Reverse ranking

Cumulative Functions:

• .cumsum() - Cumulative sum
• .cumprod() - Cumulative product
• .cummax() - Cumulative maximum
• .cummin() - Cumulative minimum