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Is there a performance difference between i++ and ++i in C++?
...forms deep copies. In such cases, there is no argument, ++i is perhaps an order of magnitude more efficient than i++. They key is to get in the habit of using pre-increment whenever post-increment semantics are not actually required by your algorithm, and you'll then be in the habit of writing cod...
What's the bad magic number error?
... dangerous script. What if a package was delivered with only .pyc files in order to keep it closed source? Oops, you just deleted the application.
– Dan Mantyla
Sep 18 '12 at 15:06
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Python __call__ special method practical example
...on in general, a dictionary works out well because you can't guarantee the order in which things fill up your list. In this case, a list might work, but it's not going to be any faster or simpler.
– S.Lott
Apr 28 '11 at 21:05
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How do I compare two strings in Perl?
...between its arguments. ...
lt, le, ge, gt and cmp use the collation (sort) order specified by the current locale if a legacy use locale (but not use locale ':not_characters') is in effect. See perllocale. Do not mix these with Unicode, only with legacy binary encodings. The standard Unicode::Collate...
correct way to use super (argument passing)
...(arg = 10)? I don't like this method, I need to know the MRO in advance in order to use it. The other method where I write a "root class" that inherits from object seems much cleaner.
– cha0site
Jan 23 '12 at 14:20
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Checking for empty queryset in Django
...ist before the check is made. In my case execution time went down by three orders.
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How do I look inside a Python object?
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I'd reverse that order.
– bayer
Jun 17 '09 at 10:19
5
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Retrieving the last record in each group - MySQL
...TH ranked_messages AS (
SELECT m.*, ROW_NUMBER() OVER (PARTITION BY name ORDER BY id DESC) AS rn
FROM messages AS m
)
SELECT * FROM ranked_messages WHERE rn = 1;
Below is the original answer I wrote for this question in 2009:
I write the solution this way:
SELECT m1.*
FROM messages m1 LEFT...
Is inject the same thing as reduce in ruby?
...many other programming languages and in Mathematics. Ruby aliases a lot in order to be intuitive to programmers with different backgrounds. If you want to use #length on an Array, you can. If you want to use #size, that's fine too!
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What is the difference between square brackets and parentheses in a regex?
...uestion uses keyword var in code, this probably is JavaScript). The use of php which runs on PCRE for preg matching will optimize away the lack of backtracking, however we're not in PHP either, so using classes [] instead of alternations | gives performance bonus as the match does not backtrack, and...