Remove all newlines from all cells of all rows and all columns of a CSV

remove_csv_newlines.py

#!/usr/bin/env python3
#
# Copyright (c) 2022 Leland Batey. All rights reserved.
#
# This work is licensed under the terms of the MIT license.
# For a copy, see <https://opensource.org/licenses/MIT>.
'''
Reads a CSV on stdin and writes a CSV on stdout. The output CSV should be
semantically identical to the input CSV, except that each cell will have
newline characters ('\n') replaced with an escaped newline ('\\n'). The
original use-case of this tool is to improve how CSVs displayed with `xsv
table` look in the terminal; see the following discussion on the XSV issue
tracker:
    https://github.com/BurntSushi/xsv/issues/275

Example CSV:

    headerOne,header2
    foo,"baz
    bar"

Hex dump of example CSV:

    $ xxd ./example.csv
    00000000: 6865 6164 6572 4f6e 652c 6865 6164 6572  headerOne,header
    00000010: 320a 666f 6f2c 2262 617a 0a62 6172 220a  2.foo,"baz.bar".

Hex dump of example CSV *after* processing to remove inter-cell newlines:

    $ cat ./example.csv | remove_csv_newlines.py | xxd
    00000000: 6865 6164 6572 4f6e 652c 6865 6164 6572  headerOne,header
    00000010: 320a 666f 6f2c 6261 7a5c 6e62 6172 0a    2.foo,baz\nbar.
'''
import csv
import sys

rdr = csv.reader(sys.stdin)
wtr = csv.writer(sys.stdout, quoting=csv.QUOTE_MINIMAL, lineterminator='\n')

for row in rdr:
    newrow = list()
    for col in row:
        col = col.replace('\n', '\\n')
        newrow.append(col)
    wtr.writerow(newrow)