How Do I Efficiently Assign Values to Specific Cells in a Pandas DataFrame?

Assigning Values to Specific Cells in Pandas DataFrames

When working with Pandas DataFrames, adjusting individual cell values is a common task. To achieve this, the .xs() function appears promising. However, it doesn't modify the original DataFrame but creates a copy instead.

Alternative Approach for Value Assignment

To overcome this limitation, employ the .at or .iat functions:

• .at (recommended): df.at['C', 'x'] = 10
• .iat (older method): df.iat[row_idx, col_idx] = 10

Both .at and .iat assign values directly to the original DataFrame, unlike .xs().

Performance Considerations

Benchmarking reveals the following performance comparison:

• .set_value: Fastest but deprecated
• .'x': Second-fastest
• .at: Third-fastest but recommended for future use

Deprecation Warning

The .set_value method is scheduled for deprecation in favor of .at and .iat. This is a key consideration when choosing the optimal function.

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