New submission from Daniel Lescohier <daniel.lescoh...@cbs.com>:
This is the implementation of codecs.Streamwriter.writelines for all
Python versions that I've checked:
def writelines(self, list):
""" Writes the concatenated list of strings to the stream
using .write().
"""
self.write(''.join(list))
This may be a problem if the 'list' parameter is a generator. The
generator may be returning millions of values, which the join will
concatenate in memory. It can surprise the programmer with large
memory use. I think join should only be used when you know the size of
your input, and this method does not know this. I think the safe
implementation of this method would be:
def writelines(self, list):
""" Writes the concatenated list of strings to the stream
using .write().
"""
write = self.write
for value in list:
write(value)
If a caller knows that it's input list would use a reasonable amount
of memory, it can get the same functionality as before by doing
stream.write(''.join(list)).
----------
components: Library (Lib)
message_count: 1.0
messages: 83322
nosy: dlesco
nosy_count: 1.0
severity: normal
status: open
title: codecs.StreamWriter.writelines problem when passed generator
versions: Python 2.5, Python 2.6, Python 2.7, Python 3.0
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Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue5445>
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