Specify Newline character ('\n') in reading csv using Python

Question

I want to read a csv file with each line dictated by a newline character ('\n') using Python 3. This is my code:

import csv
with open(input_data.csv, newline ='\n') as f:
        csvread = csv.reader(f)
        batch_data = [line for line in csvread]

This above code gave error:

batch_data = [line for line in csvread].
_csv.Error: new-line character seen in unquoted field - do you need to open the file in universal-newline mode?

Reading these posts: CSV new-line character seen in unquoted field error, also tried these alternatives that I could think about:

with open(input_data.csv, 'rU', newline ='\n') as f:
        csvread = csv.reader(f)
        batch_data = [line for line in csvread]


with open(input_data.csv, 'rU', newline ="\n") as f:
        csvread = csv.reader(f)
        batch_data = [line for line in csvread]

No luck of geting this correct yet. Any suggestions?

I am also reading the documentation about newline： if newline='' is not specified, newlines embedded inside quoted fields will not be interpreted correctly, and on platforms that use \r\n line 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.

So my understanding of this newline method is:

1) it is a necessity,

2) does it indicate the input file would be split into lines by empty space character?

Answer 1

1. newline='' is correct in all csv cases, and failing to specify it is an error in many cases. The docs recommend it for the very reason you're encountering.

2. newline='' doesn't mean "empty space" is used for splitting; it's specifically documented on the open function:

If [newline] is '', universal newlines mode is enabled, but line endings are returned to the caller untranslated.

So with newline='' all original \r and \n characters are returned unchanged. Normally, in universal newlines mode, any newline like sequence (\r, \n, or \r\n) is converted to \n in the input. But you don't want this for CSV input, because CSV dialects are often quite picky about what constitutes a newline (Excel dialect requires \r\n only).

Your code should be:

import csv
with open('input_data.csv', newline='') as f:
    csvread = csv.reader(f)
    batch_data = list(csvread)

If that doesn't work, you need to look at your CSV dialect and make sure you're initializing csv.reader correctly.