python readline by '\r\n'

Question

How can I called f.readline() where the line delimeter is \r\n ?

This CSV file is very large so I can't do f.read().split('\r\n').

Instead I'm hoping for f.readline('\r\n').

Here is a typical line:

1, "ABC", "the quick \n brown fox \n jumps over the \n lazy dogs", 5 \r\n

Why do you want to specify that delimiter manually? `readline` should use it automatically by default. — Konrad Rudolph, Sep 19 '13 at 15:19
Similar: http://stackoverflow.com/questions/9237246/python-how-to-read-file-with-nul-delimited-lines — UltraInstinct, Sep 19 '13 at 15:21
this file is 8GB, I can't `split`. Perhaps I an read a few lines `split` and keep the remainder — john mangual, Sep 19 '13 at 15:23
use [`io.open`](http://docs.python.org/2/library/io#io.open) to open the file and specify the `newline` parameter. — mata, Sep 19 '13 at 15:27

score 3 · Accepted Answer · answered Sep 19 '13 at 15:25

It seems you're actually trying to read a CSV file (or something like it) where newlines that are embedded in quotes need to be ignored.

That's something the csv module already handles for you.

import csv
with open("myfile", "rb") as infile:
    reader = csv.reader(infile, delimiter=",", skipinitialspaces=True)
    for line in reader:
       print line

score 1 · Answer 2 · answered Sep 19 '13 at 15:57

1

If you don't use csv, then open the file with universal newlines support:

f = open('big_csv_file.csv', 'rU')

This will cause f.readline() to interpret \n, \r\n and \r equally, each as a newline.

answered Sep 19 '13 at 15:57

Robᵩ

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score 0 · Answer 3 · answered Sep 19 '13 at 15:26

From the csv python documentation

>>> import csv
>>> with open('eggs.csv', 'rb') as csvfile:
...     spamreader = csv.reader(csvfile, delimiter=' ', quotechar='|') #<--- Note the
                                                                       #delimiter param.
...     for row in spamreader:
...         print ', '.join(row)
Spam, Spam, Spam, Spam, Spam, Baked Beans
Spam, Lovely Spam, Wonderful Spam

Just make a csvreader with delimiter set to '\r\n'. That should give you each line delimited by \r\n.

python readline by '\r\n'

3 Answers3