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When is std::weak_ptr useful?
...udying smart pointers of C++11 and I don't see any useful use of std::weak_ptr . Can someone tell me when std::weak_ptr is useful/necessary?
...
Traversing text in Insert mode
... edited May 29 '19 at 11:42
I_Don't_Code
7788 bronze badges
answered Nov 15 '09 at 11:13
P ShvedP Shved
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Obtain Bundle Identifier programmatically
...n approach to get the value. ARC example is following:
NSString *value = (__bridge_transfer NSString *)CFDictionaryGetValue(CFBundleGetInfoDictionary(CFBundleGetMainBundle()),
(const void *)(@"CFBundleIdentifier"));
...
Reset auto increment counter in postgres
... column, then the sequence is not simply called product, but rather product_id_seq (that is, ${table}_${column}_seq).
This is the ALTER SEQUENCE command you need:
ALTER SEQUENCE product_id_seq RESTART WITH 1453
You can see the sequences in your database using the \ds command in psql. If you do \...
When is -XAllowAmbiguousTypes appropriate?
... Foo a where
whichOne :: a -> String
instance Foo a where
whichOne _ = "a"
instance Foo [a] where
whichOne _ = "[a]"
-- |
-- >>> main
-- [a]
main :: IO ()
main = putStrLn $ whichOne (undefined :: [Int])
But GHC is not okay with overlapping instances when neither is clearly a b...
Retrieve list of tasks in a queue in Celery
...
if you are using rabbitMQ, use this in terminal:
sudo rabbitmqctl list_queues
it will print list of queues with number of pending tasks. for example:
Listing queues ...
0b27d8c59fba4974893ec22d478a7093 0
0e0a2da9828a48bc86fe993b210d984f 0
10@torob2.celery.pidbox 0
11926b79e30a4f0a9d95d...
Why does installing Nokogiri on Mac OS fail with libiconv is missing?
...official solution from the Nokogiri docs (nokogiri.org/tutorials/installing_nokogiri.html#mac_os_x), and the only one that worked on El Capitan. The accepted solution did not work there.
– Johannes
Oct 17 '15 at 20:11
...
How to declare an array in Python?
...are known at write-time, you could just write it as a literal like this: my_2x2_list = [[a, b], [c, d]]. Depending on what you need multi-dimensional arrays for, you also might consider using numpy, which defines array types for multi-dimensional, homogeneous, unboxed arrays that can be much more ef...
Is it possible to modify variable in python that is in outer, but not global, scope?
...ld a temporary scope. It's like the mutable but a bit prettier.
def outer_fn():
class FnScope:
b = 5
c = 6
def inner_fn():
FnScope.b += 1
FnScope.c += FnScope.b
inner_fn()
inner_fn()
inner_fn()
This yields the following interactive output:
>>> outer...
Why does pattern matching in Scala not work with variables?
...atch {
case `target` => println("It was" + target)
case _ => println("It was something else")
}
}
def mMatch2(s: String) = {
val Target: String = "a"
s match {
case Target => println("It was" + Target)
case _ => println("It was something else"...