append 도 그냥 return 만 하고 자동 업데이트 안해서 뻘짓가능
pandas 자체 성격이 그런듯
Pandas Notion
Dataframe Similars
Vectorized operation
import pandas as pd import numpy as np import time # Sample DataFrame data = pd.DataFrame({ 'A': np.random.rand(1000000), 'B': np.random.rand(1000000) }) # Non-vectorized approach def non_vectorized(df): start_time = time.time() df['C'] = df.apply(lambda row: row['A'] * row['B'], axis=1) print(f"Non-vectorized: {time.time() - start_time:.4f} sec") # Vectorized approach def vectorized(df): start_time = time.time() df['C'] = df['A'] * df['B'] print(f"Vectorized: {time.time() - start_time:.4f} secs") # Usage example non_vectorized(data.copy()) vectorized(data.copy()) #Non-vectorized: 7.0205 sec #Vectorized: 0.0045 secs