On 28 May 2015 at 03:16, Steven D'Aprano <st...@pearwood.info> wrote:
> I'd like to return a custom file object, say my own subclass. I can easily
> subclass the file object:
>
>
> from io import TextIOWrapper
> class MyFile(TextIOWrapper):
> pass
>
>
> but how do I tell open() to use MyFile?
Does the below do what you want?
#!/usr/bin/env python3
class Wrapper:
def __init__(self, wrapped):
self._wrapped = wrapped
def __getattr__(self, attrname):
return getattr(self._wrapped, attrname)
# Special methods are not resolved by __getattr__
def __iter__(self):
return self._wrapped.__iter__()
def __enter__(self):
return self._wrapped.__enter__()
def __exit__(self, *args):
return self._wrapped.__exit__(*args)
class WrapFile(Wrapper):
def write(self):
return "Writing..."
f = WrapFile(open('wrap.py'))
print(f.readline())
with f:
print(len(list(f)))
print(f.write())
>
> Answers for Python 3, thanks.
Tested on 3.2.
--
Oscar
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