New submission from Raymond Hettinger:
It is a somewhat common pattern to write:
try:
do_something()
except SomeException:
pass
To search examples in the standard library (or any other code base) use:
$ egrep -C2 "except( [A-Za-z]+)?:" *py | grep -C2 "pass"
In the Python2.7 Lib directory alone, we find 213 examples.
I suggest a context manager be added that can ignore specifie exceptions.
Here's a possible implementation:
class Ignore:
''' Context manager to ignore particular exceptions'''
def __init__(self, *ignored_exceptions):
self.ignored_exceptions = ignored_exceptions
def __enter__(self):
return self
def __exit__(self, exctype, excinst, exctb):
return exctype in self.ignored_exceptions
The usage would be something like this:
with Ignore(IndexError, KeyError):
print(s[t])
Here's a real-world example taken from zipfile.py:
def _check_zipfile(fp):
try:
if _EndRecData(fp):
return True # file has correct magic number
except IOError:
pass
return False
With Ignore() context manager, the code cleans-up nicely:
def _check_zipfile(fp):
with Ignore(IOError):
return bool(EndRecData(fp)) # file has correct magic number
return False
I think this would make a nice addition to contextlib.
----------
assignee: ncoghlan
messages: 169337
nosy: ncoghlan, rhettinger
priority: low
severity: normal
status: open
title: Add context manager for the "try: ... except: pass" pattern
type: enhancement
versions: Python 3.4
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue15806>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe:
http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
