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Iterate keys in a C++ map
...te on the keys instead of the pairs), then take a look at Boost's transform_iterator.
[Tip: when looking at Boost documentation for a new class, read the "examples" at the end first. You then have a sporting chance of figuring out what on earth the rest of it is talking about :-)]
...
What's a good rate limiting algorithm?
...sages
per = 8.0; // unit: seconds
allowance = rate; // unit: messages
last_check = now(); // floating-point, e.g. usec accuracy. Unit: seconds
when (message_received):
current = now();
time_passed = current - last_check;
last_check = current;
allowance += time_passed * (rate / per);
if (...
Python: Tuples/dictionaries as keys, select, sort
...u wish.
For this case, I'd use the following class:
class Fruit:
def __init__(self, name, color, quantity):
self.name = name
self.color = color
self.quantity = quantity
def __str__(self):
return "Name: %s, Color: %s, Quantity: %s" % \
(self.name, self...
如何查看Oracle用户的SQL执行历史记录? - 数据库(内核) - 清泛网 - 专注C/...
...e用户的SQL执行历史记录?select * from v$sqlarea t order by t LAST_ACTIVE_TIME desc注意 :执行此语句等等一些相关的语句 必须具有DBA 的权限 虽然
select * from v$sqlarea t order by t.LAST_ACTIVE_TIME desc
注意 :执行此语句等等一些相关的语句 必...
Get Unix Epoch Time in Swift
...alSince1970)
let preciseMilliseconds = Int(Date().timeIntervalSince1970 * 1_000)
let preciseMicroseconds = Int(Date().timeIntervalSince1970 * 1_000_000) // most likely precise
Unfortunately, however, in the year 2038, 32-bit numbers won't be usable for the Unix timestamp and they'll have to be 64-...
What is the best way to create constants in Objective-C
...s, enum is great and you absolutely should use it. (Even better, use the NS_ENUM and NS_OPTIONS macros.) For other things, you must use something else; enum does not do anything but integers.
And other questions
I was thinking about importing the file in the Reddit-Prefix.pch file to make the c...
Why is TypedReference behind the scenes? It's so fast and safe… almost magical!
...
Short answer: portability.
While __arglist, __makeref, and __refvalue are language extensions and are undocumented in the C# Language Specification, the constructs used to implement them under the hood (vararg calling convention, TypedReference type, arglist...
How to optimize for-comprehensions and loops in Scala?
...ormance in simple cases:
http://groups.google.com/group/scala-user/browse_thread/thread/86adb44d72ef4498
http://groups.google.com/group/scala-language/browse_thread/thread/94740a10205dddd2
Here is the issue in the bug tracker:
https://issues.scala-lang.org/browse/SI-4633
Update 5/28:
As a sho...
Why does C++11 not support designated initializer lists as C99? [closed]
...kery, so just sharing for fun.
#define with(T, ...)\
([&]{ T ${}; __VA_ARGS__; return $; }())
And use it like:
MyFunction(with(Params,
$.Name = "Foo Bar",
$.Age = 18
));
which expands to:
MyFunction(([&] {
Params ${};
$.Name = "Foo Bar", $.Age = 18;
return $;
}()));
...
How can I quickly sum all numbers in a file?
...ing as the awk solution in Ayman Hourieh's answer:
% perl -nle '$sum += $_ } END { print $sum'
If you're curious what Perl one-liners do, you can deparse them:
% perl -MO=Deparse -nle '$sum += $_ } END { print $sum'
The result is a more verbose version of the program, in a form that no one ...