How to Prevent Blank Lines in CSV Files Written with Python?

CSV Files Written with Python: Resolving Blank Lines Between Rows

The issue stems from the way Python's csv.writer module handles line endings. When operating in translated text mode (the default setting), it writes both a carriage return (r) and a newline (n) into the file for each line. This can cause extra blank lines when viewed in Microsoft Excel on Windows.

Solution:

To prevent these blank lines, it is crucial to open the output file in untranslated text mode. In Python 3, use the following syntax:

with open('/pythonwork/thefile_subset11.csv', 'w', newline='') as outfile:
    writer = csv.writer(outfile)

The empty string ('') as the value for the newline parameter ensures that no line termination characters are added, thus resolving the blank line issue.

Additional Notes:

• If using the Path module, you can write to the file in untranslated text mode as follows:

from pathlib import Path

with Path('/pythonwork/thefile_subset11.csv').open('w', newline='') as outfile:
    writer = csv.writer(outfile)

• For in-memory string output, use StringIO:

from io import StringIO

s = StringIO()
writer = csv.writer(s)
writer.writerow([1,2,3])

Note that the resulting string will still contain the Windows line terminator rn. To avoid this, use the newline='' parameter when writing the string to a file.

• In Python 2, open the output file in binary mode ('wb') instead of text mode ('w'). This will prevent line termination translation.

The above is the detailed content of How to Prevent Blank Lines in CSV Files Written with Python?. For more information, please follow other related articles on the PHP Chinese website!