CSV in Python adding an extra carriage return on Windows

Question

import csv outfile   file  test csv    w   writer   csv writer outfile  delimiter      quoting csv QUOTE MINIMAL  writer writerow   hi   dude    writer writerow   hi2   dude2    outfile close     It generates a file  test csv  with an extra  r at each row  like so   test csv  hi dude r r nhi2 dude2 r r n   instead of the expected   hi dude r nhi2 dude2 r n   Why is this happening  or is this actually the desired behavior   Note    This behavior can occur with Python 2 or 3

User · Answer

In Python 3  I haven t tried this in Python 2   you can also simply do  with open  output csv   w  newline     as f      writer csv writer f      writer writerow mystuff            as per documentation   More on this in the doc s footnote      If newline    is not specified  newlines embedded inside quoted fields   will not be interpreted correctly  and on platforms that use  r n   linendings on write an extra  r will be added  It should always be   safe to specify newline     since the csv module does its own    universal  newline handling

User · Answer

While  john-machin gives a good answer  it s not always the best approach  For example  it doesn t work on Python 3 unless you encode all of your inputs to the CSV writer  Also  it doesn t address the issue if the script wants to use sys stdout as the stream   I suggest instead setting the  lineterminator  attribute when creating the writer   import csv import sys  doc   csv writer sys stdout  lineterminator   n   doc writerow  abc   doc writerow range 3     That example will work on Python 2 and Python 3 and won t produce the unwanted newline characters  Note  however  that it may produce undesirable newlines  omitting the LF character on Unix operating systems    In most cases  however  I believe that behavior is preferable and more natural than treating all CSV as a binary format  I provide this answer as an alternative for your consideration

User · Answer

You have to add attribute newline   n  to open function like this   with open  file csv   w  newline   n   as out      csv out   csv writer out  delimiter

User · Answer

You can introduce the  lineterminator   n  parameter in the csv writer command   import csv delimiter   t  with open  tmp csv     w   encoding  utf-8   as stream      writer   csv writer stream  delimiter delimiter  quoting csv QUOTE NONE  quotechar      lineterminator   n       writer writerow   A1     B1    C1        writer writerow   A2     B2    C2        writer writerow   A3     B3    C3

User · Answer

Python 3  The official csv documentation recommends opening the file with newline    on all platforms to disable universal newlines translation  with open  output csv    w   newline     encoding  utf-8   as f      writer   csv writer f           The CSV writer terminates each line with the lineterminator of the dialect  which is  r n for the default excel dialect on all platforms   Python 2  On Windows  always open your files in binary mode   quot rb quot  or  quot wb quot    before passing them to csv reader or csv writer  Although the file is a text file  CSV is regarded a binary format by the libraries involved  with  r n separating records  If that separator is written in text mode  the Python runtime replaces the  n with  r n  hence the  r r n observed in the file  See this previous answer

User · Answer

Note that if you use DictWriter  you will have a new line from the open function and a new line from the writerow function  You can use newline    within the open function to remove the extra newline

[python] CSV in Python adding an extra carriage return, on Windows

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