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How to avoid having class data shared among instances?
...problem you face is that x.list and y.list are the same list, so when you call append on one, it affects the other.
– Matt Moriarity
Nov 5 '09 at 14:04
...
Creating the Singleton design pattern in PHP5
...
/**
* Singleton class
*
*/
final class UserFactory
{
/**
* Call this method to get singleton
*
* @return UserFactory
*/
public static function Instance()
{
static $inst = null;
if ($inst === null) {
$inst = new UserFactory();
...
Fastest way to list all primes below N
...4.0 |
| sundaram3 | 416.0 |
+---------------------+-------+
Of all the methods tested, allowing numpy, for n=1000000,
primesfrom2to was the fastest tested.
+---------------------+-------+
| Method | ms |
+---------------------+-------+
| primesfrom2to | 15.9 |
| p...
Python != operation vs “is not”
...right hand side and the left hand side are the very same object. No methodcalls are done, objects can't influence the is operation.
You use is (and is not) for singletons, like None, where you don't care about objects that might want to pretend to be None or where you want to protect against object...
How to change the CHARACTER SET (and COLLATION) throughout a database?
...
Do you really need to use "ALTER TABLE <table_name> MODIFY <column_name> ...". According to dev.mysql.com/doc/refman/5.5/en/alter-table.html it seems "ALTER TABLE <table_name> CONVERT TO CHARACTER SET ..." also chan...
What is the most efficient way to store a list in the Django models?
...
This is probably what I will end up doing, but I was really hoping the underlying structure for this would have been built in. I guess I am to o lazy.
– grieve
Jul 10 '09 at 16:11
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Logging uncaught exceptions in Python
... global type (much like using var self = this in Javascript). It doesn't really matter unless you need to access the type object inside your function, in which case you can use type_ as the argument instead.
– Ryan P
Jan 2 '13 at 17:08
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Truncating all tables in a Postgres database
I regularly need to delete all the data from my PostgreSQL database before a rebuild. How would I do this directly in SQL?
...
Python - Create a list with initial capacity
...bject %d" % ( i, )
result.append(message)
return result
def doAllocate( size=10000 ):
result=size*[None]
for i in range(size):
message= "some unique object %d" % ( i, )
result[i]= message
return result
Results. (evaluate each function 144 times and average ...
What does “#define _GNU_SOURCE” imply?
...
For exact details on what are all enabled by _GNU_SOURCE, documentation can help.
From the GNU documentation:
Macro: _GNU_SOURCE
If you define this macro, everything is included: ISO C89, ISO C99, POSIX.1, POSIX.2, BSD, SVID, X/Open, LFS, and ...