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Fastest check if row exists in PostgreSQL
...ex on contact, it can usually reduce time cost to 1 ms.
CREATE INDEX index_contact on contact(id);
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View a list of recent documents in Vim
...bro ol" is an abbreviation of ":browse oldfiles"
– Mr_Chimp
Sep 22 '11 at 16:04
28
To open one of...
How can I load storyboard programmatically from class?
...cond = "SecondViewController"
}
extension UIStoryBoard{
class func load(_ storyboard: StoryBoardName) -> UIViewController{
return UIStoryboard(name: storyboard.rawValue, bundle: nil).instantiateViewController(withIdentifier: storyboard.rawValue)
}
}
and then you can load your Storyb...
JavaScript Chart Library
...s of JavaScript solutions for graphics that do not require Flash:
Canvas-based, rendered in IE using ExplorerCanvas that in turns relies on VML
SVG on standard-based browsers, rendered as VML in IE
There are pros and cons of both approaches but for a charting library I would recommend the later ...
GitHub: Permission denied (publickey). fatal: The remote end hung up unexpectedly
... this solution seems very close to what has already been posted by learner_19
– Erik
Sep 17 '14 at 7:49
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Age from birthdate in python
...t(True) is 1 and int(False) is 0:
from datetime import date
def calculate_age(born):
today = date.today()
return today.year - born.year - ((today.month, today.day) < (born.month, born.day))
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mysql Foreign key constraint is incorrectly formed error
...ISAM engine. It's a silly mistake, which I fixed with:
ALTER TABLE parent_table ENGINE=InnoDB;
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How does tuple comparison work in Python?
...
@CMCDragonkai -- yes. try: x = tuple([0 for _ in range(n)]) and do the same for y. Setting n=100, 1000, 10,000, and 100,000 and running %timeit x==y gave timing values of .5, 4.6, 43.9, and 443 microseconds respectively, which is about as close to O(n) as you can pra...
Is it unnecessary to put super() in constructor?
...) is a compiler error so it must be specified.
For example:
public class Base { }
public class Derived extends Base { }
This is fine because if you add no constructor explicitly Java puts in a public default constructor for you.
public class Base { }
public class Derived extends Base { public D...
Check if a table exists in Rails
...tables/views, collectively data sources.
# Tables and views
ActiveRecord::Base.connection.data_sources
ActiveRecord::Base.connection.data_source_exists? 'kittens'
# Tables
ActiveRecord::Base.connection.tables
ActiveRecord::Base.connection.table_exists? 'kittens'
# Views
ActiveRecord::Base.connect...