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How to pull a random record using Django's ORM?
...ust one query (assuming Postgres):
random_instance_or_none = Model.objects.raw('''
select * from {0} limit 1
offset floor(random() * (select count(*) from {0}))
'''.format(Model._meta.db_table)).first()
Be aware that this will raise an index error if the table is empty. Write yourself a mod...
Chaining multiple MapReduce jobs in Hadoop
...uture version will support Riffle annotations, but it works great now with raw MR JobConf jobs.
A variant on this is to not manage MR jobs by hand at all, but develop your application using the Cascading API. Then the JobConf and job chaining is handled internally via the Cascading planner and Flow...
Saving and Reading Bitmaps/Images from Internal memory in Android
...that you write it again, i suppose you have that image data as a bitmap or raw data in the form of byte-array. If you have bitmap, you can directly utilize the above functions. If you have it in the form of byte array, use this to convert it to bitmap Bitmap bitmap = BitmapFactory.decodeByteArray(bi...
.gitignore and “The following untracked working tree files would be overwritten by checkout”
... This is exactly the problem I had, a file path was different by one letter case - Windows treats this as same but GIT does not which is the problem.
– Daniel Sokolowski
Aug 1 '15 at 3:19
...
Set time to 00:00:00
...merica/Montreal, Africa/Casablanca, or Pacific/Auckland. Never use the 2-4 letter abbreviation such as EST or IST as they are not true time zones, not standardized, and not even unique(!).
ZoneId z = ZoneId.of( "America/Montreal" ) ;
ZonedDateTime
Apply the ZoneId to the Instant to get a ZonedD...
Is putting a div inside an anchor ever correct?
...119]. However, for readability, these words do not appear in all uppercase letters in this specification.
With that in mind, I believe the definitive statement is in 7.5.3 Block-level and inline elements, where it says
Generally, inline elements may contain only data and other inline elements....
What's the difference between SortedList and SortedDictionary?
...-+------------+------------------+
To roughly paraphrase, if you require raw performance SortedDictionary could be a better choice. If you require lesser memory overhead and indexed retrieval SortedList fits better. See this question for more on when to use which.
You can read more here, here, he...
MYSQL OR vs IN performance
...e is the simplest possible use case. Using Eloquent for syntax simplicity, raw SQL equivalent executes the same.
$t = microtime(true);
for($i=0; $i<10000; $i++):
$q = DB::table('users')->where('id',1)
->orWhere('id',2)
->orWhere('id',3)
->orWhere('id',4)
->orWhere...
Remove all special characters from a string [duplicate]
...nything and have them stripped of all special characters so they only have letters and numbers and of course I would like to replace spaces with hyphens.
...
how to make twitter bootstrap submenu to open on the left side?
...the window and goes too much to the right, so that user can see only first letters. How to make that submenu to open not to the right, but to the left?
...