Skipping Headers When Processing CSV Files Using Python

When working with CSV (Comma-Separated Values) files containing headers, it's often necessary to exclude these headers during processing. This article addresses a common problem faced when attempting to skip headers in Python.

The provided code snippet encounters an issue where the header row is affected by the applied functions. To rectify this, readers should note that the reader variable iterates over rows in the CSV file.

To skip one row before the main loop, where the row index starts from 1, use the next() function as follows:

next(reader, None)  # Skip header by returning None if the reader is empty

Additionally, to enhance readability and simplify file handling, context managers can be employed:

with open("tmob_notcleaned.csv", "rb") as infile:
    with open("tmob_cleaned.csv", "wb") as outfile:
        reader = csv.reader(infile)
        next(reader, None)  # Skip headers
        writer = csv.writer(outfile)
        for row in reader:
            # Process rows here

Alternatively, to include the header row in the output file, simply pass the headers variable, which can be initialized using next(), to the writer:

headers = next(reader, None)  # Get headers or None if empty
if headers:
    writer.writerow(headers)

By following these techniques, developers can effectively skip headers and process CSV files with ease.