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Pandas DataFrame MemoryError When Using concat() on Large DataFrames with NaN Values

👀 Views: 100 đŸ’Ŧ Answers: 1 📅 Created: 2025-06-06
pandas dataframe memoryerror Python

Hey everyone, I'm running into an issue that's driving me crazy. I've looked through the documentation and I'm still confused about I'm working with a `MemoryError` when trying to concatenate two large DataFrames that contain a important number of NaN values. I'm using `pandas` version 1.3.5 and have two DataFrames, `df1` and `df2`, that I'm attempting to concatenate along the rows. Both DataFrames are around 5 million rows each, and when I attempt the following code: ```python import pandas as pd df1 = pd.DataFrame({'A': range(5000000), 'B': [None] * 5000000}) df2 = pd.DataFrame({'A': range(5000000, 10000000), 'B': [None] * 5000000}) result = pd.concat([df1, df2], ignore_index=True) ``` I get the following behavior message: ``` MemoryError: Unable to allocate 37.2 MiB for an array with shape (10000000,) and data type object ``` I have tried increasing my system's virtual memory but it hasn't helped. I've also looked into using `pd.concat()` with the `sort=False` parameter since I read that it could improve performance, but the MemoryError continues. Is there a more efficient way to handle concatenation of large DataFrames with many NaN values? Should I consider using a different approach like Dask or chunking the DataFrames before concatenating? Any advice on how to mitigate this scenario would be greatly appreciated. My development environment is Ubuntu. Thanks in advance!