codecs, csv issues

[George Sakkis]

I'm trying to use codecs.open() and I see two issues when I pass
encoding='utf8':

1) Newlines are hardcoded to LINEFEED (ascii 10) instead of the
platform-specific byte(s).

import codecs
f = codecs.open('tmp.txt', 'w', encoding='utf8')
s = u'\u0391\u03b8\u03ae\u03bd\u03b1'
print >> f, s
print >> f, s
f.close()

This doesn't happen for the default encoding (=None).

2) csv.writer doesn't seem to work as expected when being passed a
codecs object; it treats it as if encoding is ascii:

import codecs, csv
f = codecs.open('tmp.txt', 'w', encoding='utf8')
s = u'\u0391\u03b8\u03ae\u03bd\u03b1'
# this works fine
print >> f, s
# this doesn't
csv.writer(f).writerow()
f.close()

Traceback (most recent call last):
....
csv.writer(f).writerow()
UnicodeEncodeError: 'ascii' codec can't encode character u'\u0391' in
position 0: ordinal not in range(128)

Is this the expected behavior or are these bugs ?

George

 

[Peter Otten]

I'm trying to use codecs.open() and I see two issues when I pass
encoding='utf8':

1) Newlines are hardcoded to LINEFEED (ascii 10) instead of the
platform-specific byte(s).

import codecs
f = codecs.open('tmp.txt', 'w', encoding='utf8')
s = u'\u0391\u03b8\u03ae\u03bd\u03b1'
print >> f, s
print >> f, s
f.close()

This doesn't happen for the default encoding (=None).

2) csv.writer doesn't seem to work as expected when being passed a
codecs object; it treats it as if encoding is ascii:

import codecs, csv
f = codecs.open('tmp.txt', 'w', encoding='utf8')
s = u'\u0391\u03b8\u03ae\u03bd\u03b1'
# this works fine
print >> f, s
# this doesn't
csv.writer(f).writerow()
f.close()

Traceback (most recent call last):
...
csv.writer(f).writerow()
UnicodeEncodeError: 'ascii' codec can't encode character u'\u0391' in
position 0: ordinal not in range(128)

Is this the expected behavior or are these bugs ?

Looking into the documentation

"""
Note: This version of the csv module doesn't support Unicode input. Also,
there are currently some issues regarding ASCII NUL characters.
Accordingly, all input should be UTF-8 or printable ASCII to be safe; see
the examples in section 9.1.5. These restrictions will be removed in the
future.
"""

and into the source code

if encoding is not None and \
'b' not in mode:
# Force opening of the file in binary mode
mode = mode + 'b'

I'd be willing to say that both are implementation limitations.

Peter

 

[John Machin]

I'm trying to use codecs.open() and I see two issues when I pass
encoding='utf8':

1) Newlines are hardcoded to LINEFEED (ascii 10) instead of the
platform-specific byte(s).

import codecs
f = codecs.open('tmp.txt', 'w', encoding='utf8')
s = u'\u0391\u03b8\u03ae\u03bd\u03b1'
print >> f, s
print >> f, s
f.close()

This is documented behaviour:
"""
Note
Files are always opened in binary mode, even if no binary mode was
specified. This is done to avoid data loss due to encodings using 8-
bit values. This means that no automatic conversion of '\n' is done on
reading and writing.
"""