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How do I create a list of random numbers without duplicates?
...ignificantly cheaper. For ranges of size N, if you want to generate on the order of N unique k-sequences or more, I recommend the accepted solution using the builtin methods random.sample(range(N),k) as this has been optimized in python for speed.
Code
# Return a randomized "range" using a Linear Co...
Why use the INCLUDE clause when creating an index?
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If the column is not in the WHERE/JOIN/GROUP BY/ORDER BY, but only in the column list in the SELECT clause.
The INCLUDE clause adds the data at the lowest/leaf level, rather than in the index tree.
This makes the index smaller because it's not part of the tree
INCLUDE co...
STL：accumulate与自定义数据类型 - C/C++ - 清泛网 - 专注C/C++及内核技术
...mulate()的原型为(文件取自DEV-C++编译器)：
template<typename _InputIterator, typename _Tp, typename _BinaryOperation>
_Tp accumulate(_InputIterator __first, _InputIterator __last, _Tp __init,
_BinaryOperation __binary_op)
{
// concept requirements
__glibcxx...
What does the caret operator (^) in Python do?
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It invokes the __xor__() or __rxor__() method of the object as needed, which for integer types does a bitwise exclusive-or.
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improv...
What are the lesser known but useful data structures?
..., sorted linked lists, with efficiency comparable to a binary search tree (order log n average time for most operations).
They can be used as an alternative to balanced trees (using probalistic balancing rather than strict enforcement of balancing). They are easy to implement and faster than say,...
Split List into Sublists with LINQ
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@Nick Order is not preserved your way though. It is still a good thing to know but you'd be grouping them into (0,3,6,9,...), (1,4,7,10,...), (2,5,8,11,...). If order doesn't matter then it is fine but in this case it sounds like i...
Define a lambda expression that raises an Exception
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There is more than one way to skin a Python:
y = lambda: (_ for _ in ()).throw(Exception('foobar'))
Lambdas accept statements. Since raise ex is a statement, you could write a general purpose raiser:
def raise_(ex):
raise ex
y = lambda: raise_(Exception('foobar'))
But if...
How to hide TabPage from TabControl [duplicate]
... A frustration is that RemoveByKey then Add later upsets the order.
– Colonel Panic
Apr 7 '15 at 16:07
@...
How does one write code that best utilizes the CPU cache to improve performance?
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I know not the origins, but for one, member order is crucial in let's say network communication, where you may want to send entire structures byte by byte over the web.
– Kobrar
Nov 4 '16 at 12:54
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List all the modules that are part of a python package?
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import email
package = email
for importer, modname, ispkg in pkgutil.iter_modules(package.__path__):
print "Found submodule %s (is a package: %s)" % (modname, ispkg)
How to import them too? You can just use __import__ as normal:
import pkgutil
# this is the package we are inspecting -- for...