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Why is reading lines from stdin much slower in C++ than Python?
...
tl;dr: Because of different default settings in C++ requiring more system calls.
By default, cin is synchronized with stdio, which causes it to avoid any input buffering. If you add this to the top of your main, you should see much better performance:
std::ios_base::sync_with_stdio(false);
Normal...
Do spurious wakeups in Java actually happen?
...thread_cond_wait() function in Linux is implemented using the futex system call. Each blocking system call on Linux returns abruptly with EINTR when the process receives a signal. ... pthread_cond_wait() can't restart the waiting because it may miss a real wakeup in the little time it was outside th...
Fastest way to get the first object from a queryset in django?
...want to first turn it into a list because that would force a full database call of all the records. Just do the above and it will only pull the first. You could even use .order_by() to ensure you get the first you want.
Be sure to add the .get() or else you will get a QuerySet back and not an object...
“icon-bar” in twitter bootstrap navigation bar
...con-bar in bootstrap.css:
.navbar-toggle .icon-bar {
display: block;
width: 22px;
height: 2px;
background-color: #cccccc;
border-radius: 1px;
}
It is a block structure, so it is aligned line by line. The background-color is set to be gray80. Actually, you can change its width, height, b...
How to make a class JSON serializable
...gt;>> magic(f)
'{"fname": "/foo/bar"}'
In that case you can merely call json.dumps(f.__dict__).
If you want more customized output then you will have to subclass JSONEncoder and implement your own custom serialization.
For a trivial example, see below.
>>> from json import JSON...
Where are my postgres *.conf files?
...based authentication file
# (change requires restart)
#ident_file = 'ConfigDir/pg_ident.conf' # ident configuration file
# (change requires restart)
# If external_pid_file is not explicitly set, no extra PID file is written.
#external_pid_file = '(none)' ...
Is it possible to override JavaScript's toString() function to provide meaningful output for debuggi
...tion overriding the prototype toString property, Object.prototype.toString.call(f) will still display [object Object].
– Frederik Krautwald
May 12 '15 at 20:59
16
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What does the exclamation mark do before the function?
...end: !function foo() {}() which has higher precedence than ! and instantly calls the function.
So what the author is doing is saving a byte per function expression; a more readable way of writing it would be this:
(function(){})();
Lastly, ! makes the expression return true. This is because by d...
How to unsubscribe to a broadcast event in angularJS. How to remove function registered via $on
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You need to store the returned function and call it to unsubscribe from the event.
var deregisterListener = $scope.$on("onViewUpdated", callMe);
deregisterListener (); // this will deregister that listener
This is found in the source code :) at least in 1.0.4. I'll ...
Optional Parameters with C++ Macros
...Hello, World!", 18, bold);
return 0;
}
This makes it easier for the caller of the macro, but not the writer.
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