Pandas

Creator
Created
Created
2019 Nov 5 3:14
Editor
Edited
Edited
2026 Jun 9 17:45
Refs
Refs
append just returns a new object without automatically updating, which can lead to mistakes
this is the nature of pandas itself
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
 
 
3.0
 

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