Convert tab-delimited txt file into a csv file using Python

Question

So I want to convert a simple tab delimited text file into a csv file. If I convert the txt file into a string using string.split(\'\\n\') I get a list with each list item a

Answer 1

Why you should always use 'rb' mode when reading files with the csv module:

Python 2.7.2 (default, Jun 12 2011, 15:08:59) [MSC v.1500 32 bit (Intel)] on win32
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What's in the sample file: any old rubbish, including control characters obtained by extracting blobs or whatever from a database, or injudicious use of the CHAR function in Excel formulas, or ...

>>> open('demo.txt', 'rb').read()
'h1\t"h2a\nh2b"\th3\r\nx1\t"x2a\r\nx2b"\tx3\r\ny1\ty2a\x1ay2b\ty3\r\n'

Python follows CP/M, MS-DOS, and Windows when it reads files in text mode: \r\n is recognised as the line separator and is served up as \n, and \x1a aka Ctrl-Z is recognised as an END-OF-FILE marker.

>>> open('demo.txt', 'r').read()
'h1\t"h2a\nh2b"\th3\nx1\t"x2a\nx2b"\tx3\ny1\ty2a' # WHOOPS

csv with a file opened with 'rb' works as expected:

>>> import csv
>>> list(csv.reader(open('demo.txt', 'rb'), delimiter='\t'))
[['h1', 'h2a\nh2b', 'h3'], ['x1', 'x2a\r\nx2b', 'x3'], ['y1', 'y2a\x1ay2b', 'y3']]

but text mode doesn't:

>>> list(csv.reader(open('demo.txt', 'r'), delimiter='\t'))
[['h1', 'h2a\nh2b', 'h3'], ['x1', 'x2a\nx2b', 'x3'], ['y1', 'y2a']]
>>>