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
Python| Pandas dataframe.append() - GeeksforGeeks
Python is a great language for doing data analysis, primarily because of the fantastic ecosystem of data-centric python packages. Pandas is one of those packages and makes importing and analyzing data much easier. Pandas dataframe.append() function is used to append rows of other dataframe to the end of the given dataframe, returning a new dataframe object.
https://www.geeksforgeeks.org/python-pandas-dataframe-append/

3.0

Seong-lae Cho