csv.writerows() puts newline after each row

Question

This is an example from the O'Reilly Cookbook (truncated dataset)

headers = ['Symbol','Price','Date','Time','Change','Volume']
rows = [{'Symbol': 'AA', 'Volume': 181800, 'Change': -0.18,
         'Time': '9:36am', 'Date': '6/11/2007', 'Price': 39.48},
        {'Symbol': 'AIG', 'Volume': 195500, 'Change': -0.15,
         'Time': '9:36am', 'Date': '6/11/2007', 'Price': 71.38} ]

with open('stocks2.csv','w') as f:
    f_csv = csv.DictWriter(f, headers)
    f_csv.writeheader()
    f_csv.writerows(rows)

the output file has a \n at the end of each line, and apparently one more at the end. When I bring it into Excel, I get blank lines between each row. The same if I open it with Notepad++.

But, if I more if from a command line, the \n don't show up.

I saw another Q&A about a \n at the end of a file - but this one is about a \n at the end of each line. (And I don't see why more doesn't give the \n.)

I plan to bring the file into OpenOffice Calc.

Answer 1

This problem occurs only with Python on Windows.

In Python v3, you need to add newline='' in the open call per:

Python 3.3 CSV.Writer writes extra blank rows

On Python v2, you need to open the file as binary with "b" in your open() call before passing to csv

Changing the line

with open('stocks2.csv','w') as f:

to:

with open('stocks2.csv','wb') as f:

will fix the problem

More info about the issue here:

CSV in Python adding an extra carriage return, on Windows

Answer 2

I came across this issue on windows for Python 3. I tried changing newline parameter while opening file and it worked properly with newline=''.

Add newline='' to open() method as follows:

with open('stocks2.csv','w', newline='') as f:
    f_csv = csv.DictWriter(f, headers)
    f_csv.writeheader()
    f_csv.writerows(rows)

It will work as charm.

Hope it helps.