Complicated Moments
loc vs iloc vs []: df['col'] selects a column. df.loc[row_label, col_label] selects by label. df.iloc[row_int, col_int] selects by integer position. After filtering, integer positions no longer match labels — always know which accessor you need.
Chain indexing creates copies unpredictably: df[df['gc'] > 0.5]['length'] = 100 may silently fail. Always use df.loc[mask, 'length'] = 100.
groupby + transform vs agg: agg reduces each group t
[Description truncada. Veja o README completo no GitHub.]