[Python-Dev] Optional separatorargument for file.writelines() and StringIO.writelines()

[Alex Martelli]

On 2004 Feb 25, at 12:13, Dmitry Vasiliev wrote:

> Raymond Hettinger wrote:
>> Currently, writelines() does not add trailing line separators..
>> This is fine when working with readlines() but a PITA in other 
>> situations.
>> If we added an optional separator argument, it would be easier to add
>> newlines and we would gain some of the flexibility of str.join() at 
>> full C speed.
>
> Maybe not a separator but suffix, so newline will be added to last 
> line too?

Good point.  And while a separator would be a slight nuisance to 
express otherwise, a "suffix" isn't -- it seems to me that 
f.writelines(x+'\n' for x in mylines) is a rather good way of 
expressing "suffix each line with a \n".  I don't think this suffixing 
operation is so widely more important than other elaborations on items 
of mylines to make it worth specialcasing into a writelines argument 
[if anything, f.writelines(str(x) for x in mylines) would be the one 
elaboration that seems to me to be by far the most frequent -- still 
not worth specialcasing though, IMHO].


Alex