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Simulate CREATE DATABASE IF NOT EXISTS for PostgreSQL?
...an work around it from within psql by executing the DDL statement conditionally:
SELECT 'CREATE DATABASE mydb'
WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = 'mydb')\gexec
The manual:
\gexec
Sends the current query buffer to the server, then treats each column of each row of the query's...
Generating Guids in Ruby
I have problem that is really easily solved with Guids.
10 Answers
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Is there a ceiling equivalent of // operator in Python?
...t shy of an order of magnitude faster than forcing the float division and calling ceil(), provided you care about the speed. Which you shouldn't, unless you've proven through usage that you need to.
>>> timeit.timeit("((5 - 1) // 4) + 1", number = 100000000)
1.7249219375662506
>>>...
Django queries - id vs pk
...ry key field i.e. you don't need to care whether the primary key field is called id or object_id or whatever.
It also provides more consistency if you have models with different primary key fields.
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Swift equivalent for MIN and MAX macros
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With Swift 5, max(_:_:) and min(_:_:) are part of the Global Numeric Functions. max(_:_:) has the following declaration:
func max<T>(_ x: T, _ y: T) -> T where T : Comparable
You can use it like this with Ints:
let maxInt = max(5,...
Exclude a directory from git diff
...t diff previous_release current_release !(spec)
Saves you having to list all other things.
Or, shell-agnostic:
git diff previous_release current_release --name-only | grep -v '^spec/' \
| xargs git diff previous_release current_release --
You could wrap that up in a one-liner shell script ...
How to use __doPostBack()
I'm trying to create an asyncrhonous postback in ASP.NET using __doPostBack() , but I have no idea how to do it. I want to use vanilla JavaScript.
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Explicitly select items from a list or tuple
... myBigList[i] for i in [87, 342, 217, 998, 500] ]
20.6 usec: map(myBigList.__getitem__, (87, 342, 217, 998, 500))
22.7 usec: itemgetter(87, 342, 217, 998, 500)(myBigList)
24.6 usec: list( myBigList[i] for i in [87, 342, 217, 998, 500] )
Note that in Python 3, the 1st was changed to be the same as ...
python list in sql query as parameter
... performed the same query. Doing this I got the erroy i.e. Type Error: not all arguments converted during string formatting. How am I supposed to solbe it
– TechJhola
Jan 9 '15 at 19:55
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Cannot change version of project facet Dynamic Web Module to 3.0?
...so I changed the library in Java Build Path to obtain the JavaSE-1.7. It's all OK up to here.
31 Answers
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