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Is there a performance difference between i++ and ++i in C++?
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However, if i is an instance of a C++ class, then i++ and ++i are making calls to one of the operator++ functions. Here's a standard pair of these functions:
Foo& Foo::operator++() // called for ++i
{
this->data += 1;
return *this;
}
Foo Foo::operator++(int ignored_dummy_value) ...
Learning Python from Ruby; Differences and Similarities
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[x*x for x in values if x > 15]
to get a new list of the squares of all values greater than 15. In Ruby, you'd have to write the following:
values.select {|v| v > 15}.map {|v| v * v}
The Ruby code doesn't feel as compact. It's also not as efficient since it first converts the values a...
What's the difference between django OneToOneField and ForeignKey?
...Guide to Django:
OneToOneField
A one-to-one relationship. Conceptually, this is similar to a ForeignKey with unique=True, but the "reverse" side of the relation will directly return a single object.
In contrast to the OneToOneField "reverse" relation, a ForeignKey "reverse" relation retur...
What is the proper way to comment functions in Python?
Is there a generally accepted way to comment functions in Python? Is the following acceptable?
10 Answers
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When to use EntityManager.find() vs EntityManager.getReference() with JPA
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I usually use getReference method when i do not need to access database state (I mean getter method). Just to change state (I mean setter method). As you should know, getReference returns a proxy object which uses a powerful featu...
Understanding slice notation
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It's pretty simple really:
a[start:stop] # items start through stop-1
a[start:] # items start through the rest of the array
a[:stop] # items from the beginning through stop-1
a[:] # a copy of the whole array
There is also...
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock'
I installed MySQL on Mac OS X Mountain Lion with homebrew install mysql , but when I tried mysql -u root I got the following error:
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How can I fix the Microsoft Visual Studio error: “package did not load correctly”?
I installed Visual Studio 2012 and DevExpress 13.1. As Visual Studio started, it generated an error shown by this attached image,
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Reliable method to get machine's MAC address in C#
...work across OS. Any ideas? I have been scraping the output of "ipconfig /all" but this is terribly unreliable as the output format differs on every machine.
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JavaScript chop/slice/trim off last character in string
...viously using the substring version. Thanks!
– Matt Ball
Apr 13 '10 at 14:09
33
forgive me if I'm...