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__getattr__ on a module
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A while ago, Guido declared that all special method lookups on
new-style classes bypass __getattr__ and __getattribute__. Dunder methods had previously worked on modules - you could, for example, use a module as a context manager simply by defining __enter__...
Get exception description and stack trace which caused an exception, all as a string
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See the traceback module, specifically the format_exc() function. Here.
import traceback
try:
raise ValueError
except ValueError:
tb = traceback.format_exc()
else:
tb = "No error"
finally:
print tb
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List all base classes in a hierarchy of given class?
...ass Foo (whether it is a new-style class or not), how do you generate all the base classes - anywhere in the inheritance hierarchy - it issubclass of?
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Check if $_POST exists
...sts and if it does, print it inside another string, if not, don't print at all.
14 Answers
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Relative imports in Python 2.7
... not determine what package Python thinks it is in. That depends, additionally, on how you load the file into Python (by running or by importing).
There are two ways to load a Python file: as the top-level script, or as a
module. A file is loaded as the top-level script if you execute it directl...
How to serialize SqlAlchemy result to JSON?
...ps(e, cls=new_alchemy_encoder(), check_circular=False)
This would encode all children, and all their children, and all their children... Potentially encode your entire database, basically. When it reaches something its encoded before, it will encode it as 'None'.
A recursive, possibly-circular, s...
How to select a single field for all documents in a MongoDB collection?
... include several fields. In the following operation, find() method returns all documents that match the query. In the result set, only the item and qty fields and, by default, the _id field return in the matching documents.
db.inventory.find( { type: 'food' }, { item: 1, qty: 1 } )
In this example ...
Inheritance and Overriding __init__ in python
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The book is a bit dated with respect to subclass-superclass calling. It's also a little dated with respect to subclassing built-in classes.
It looks like this nowadays:
class FileInfo(dict):
"""store file metadata"""
def __init__(self, filename=None):
super(FileInfo,...
The object 'DF__*' is dependent on column '*' - Changing int to double
Basically I got a table in my EF database with the following properties:
8 Answers
8
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MySQL DROP all tables, ignoring foreign keys
Is there a nice easy way to drop all tables from a MySQL database, ignoring any foreign key constraints that may be in there?
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