大约有 32,000 项符合查询结果（耗时：0.0620秒） [XML]
Is there a simple, elegant way to define singletons? [duplicate]
...etons. All you have to do is decorate the class; to get the singleton, you then have to use the Instance method. Here's an example:
@Singleton
class Foo:
def __init__(self):
print 'Foo created'
f = Foo() # Error, this isn't how you get the instance of a singleton
f = Foo.instance() # ...
SQL SELECT speed int vs varchar
...-Benz and 1. And in main table column Brands and value 1. And when SELECT, then at first get Id from table car_brands and then SELECT Something FROM main_table WHERE Brands = (SELECT Id FROM car_brands WHERE Brands = Mercedes-Benz). Or some other approach?
– Andris
...
Fastest way to check a string contain another substring in JavaScript?
...ugh (so if you left it out because it always performs worse than indexOf() then that's fine, maybe add a note to that effect.) EDIT: this JSperf link shows some interesting results. Short version: indexOf() is the fastest of all methods, but this may vary based on string length and any repeating pat...
Git Push Error: insufficient permission for adding an object to repository database
...1 or some mask, try running:
git config core.sharedRepository group
and then re-run the recursive chmod and chgrp (see "Repair Permissions" above).
The operating system doesn't interpret a setgid bit on directories as "all new files and subdirectories should inherit the group owner".
When core.s...
What are the best practices for catching and re-throwing exceptions?
...ror code. If you're only able to meaningfully handle some of those errors, then you probably want to catch, inspect, and if you can't handle the error - rethrow.
– Mark Amery
Sep 4 '14 at 16:47
...
How to sort mongodb with pymongo
...key and direction as parameters.
So if you want to sort by, let's say, id then you should .sort("_id", 1)
For multiple fields:
.sort([("field1", pymongo.ASCENDING), ("field2", pymongo.DESCENDING)])
share
|
...
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.al
...enddate))
selected = r[mask]
looks correct. However, if you do want and, then instead of a and b use (a-b).any() or (a-b).all().
share
|
improve this answer
|
follow
...
Database Structure for Tree Data Structure
...
If you have to use Relational DataBase to organize tree data structure then Postgresql has cool ltree module that provides data type for representing labels of data stored in a hierarchical tree-like structure. You can get the idea from there.(For more information see: http://www.postgresql.org/...
Capture keyboardinterrupt in Python without try-except
...
I know this is an old question but I came here first and then discovered the atexit module. I do not know about its cross-platform track record or a full list of caveats yet, but so far it is exactly what I was looking for in trying to handle post-KeyboardInterrupt cleanup on Linux...
No route matches “/users/sign_out” devise rails 3
...he attacker just has to use a form with action="DELETE" on the target url, then auto-submit it at the page load).
– Maël Nison
Mar 11 '13 at 4:02
...