How to avoid pandas creating an index in a saved csv?

By default, when you save a DataFrame to a CSV file using df.to_csv(...), Pandas includes the DataFrame’s index as the first column in the output. If you’d prefer not to save the index, simply pass index=False:

import pandas as pd

# Example DataFrame
df = pd.DataFrame({
    "Name": ["Alice", "Bob", "Charlie"],
    "Age": [25, 30, 35],
    "City": ["New York", "Chicago", "San Francisco"]
})

# Save to CSV without including the index
df.to_csv("output.csv", index=False)

1. index=False instructs Pandas not to write row labels (the index) into the CSV file.
2. This results in a CSV file that only contains your data columns (plus headers), without the extra first column for the index.

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Extra Tip

• If your DataFrame has a meaningful index that you want as a separate column in the CSV, you can either:
  1. Reset the index to a column, then save without the “new” index:

     df.reset_index(inplace=True)
     df.to_csv("output_with_index_col.csv", index=False)
     

  2. Or just keep the default index=True if you prefer the original index in the CSV.

Further Learning

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