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PostgreSQL error 'Could not connect to server: No such file or directory'
...u are on OS X
Here is the fix:
Stop the database
cd /var
sudo rm -r pgsql_socket
sudo ln -s /tmp pgsql_socket
chown _postgres:_postgres pgsql_socket
Restart PostgreSQL (not your computer)
More information is available at "postgresql 9.0.3. on Lion Dev Preview 1".
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Change priorityQueue to max priorityqueue
...unction, names its input parameters x and y and returns y-x, which is basically what the int comparator class does except it returns x-y
– Edi Bice
Jun 22 '17 at 19:44
15
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Python add item to the tuple
... @SIslam Without the comma, it will just be interpreted as brackets usually used to get around the order of precedence: (a+b)*c
– Joseph Young
Feb 25 '16 at 5:54
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The difference between fork(), vfork(), exec() and clone()
...d I expected there to be a huge amount of information on this, but there really wasn't any solid comparison between the four calls.
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How can I use a DLL file from Python?
...hlapi32.dll")
# Set up prototype and parameters for the desired function call.
# HLLAPI
hllApiProto = ctypes.WINFUNCTYPE (
ctypes.c_int, # Return type.
ctypes.c_void_p, # Parameters 1 ...
ctypes.c_void_p,
ctypes.c_void_p,
ctypes.c_void_p) # ... thru 4.
hllApiParams = (...
Why does int i = 1024 * 1024 * 1024 * 1024 compile without error?
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@WouterLievens, overflow is normally an "unusual" condition, if not an outright error condition. It is a result of finite-precision math, which most people are not intuitively expecting to happen when they do math. In some cases, like -1 + 1, it's harmless;...
Mean per group in a data.frame [duplicate]
... the many ways to specify the variables to act on. Here, vars(-Month) says all variables except Month.
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Knight's Shortest Path on Chessboard
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You have a graph here, where all available moves are connected (value=1), and unavailable moves are disconnected (value=0), the sparse matrix would be like:
(a1,b3)=1,
(a1,c2)=1,
.....
And the shortest path of two points in a graph can be found usin...
LINQ query on a DataTable
...s.Cast<DataRow>().Where(myRow => (int)myRow["RowNo"] == 1). Personally, I don't find the call to AsEnumerable() any more complicated than the call to Cast<DataRow>(). As far as I know, the performance is the same, so it's just a matter of preference.
– Collin K
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Git Bash doesn't see my PATH
...ecutable names without extensions. In my case, I wanted to execute a file called cup.bat. In a Windows shell, typing cup would be enough. Bash doesn't work this way, it wants the full name. Typing cup.bat solved the problem. (I wasn't able to run the file though, since apparently bash couldn't under...