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When should I make explicit use of the `this` pointer?
...w to treat i, since it may or may not exist in all instantiations of A. In order to tell it that i is indeed a member of A<T>, for any T, the this-> prefix is required.
Note: it is possible to still omit this-> prefix by using:
template<class T>
struct B : A<T> {
using...
Firebug-like debugger for Google Chrome
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You can set this bookmarklet in your "Bookmarks Bar" in order to have Firebug lite always available in Chrome/Chromium browser (put this as the URL):
javascript:var firebug=document.createElement('script');firebug.setAttribute('src','http://getfirebug.com/releases/lite/1.2/firebu...
How to sort a dataframe by multiple column(s)
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You can use the order() function directly without resorting to add-on tools -- see this simpler answer which uses a trick right from the top of the example(order) code:
R> dd[with(dd, order(-z, b)), ]
b x y z
4 Low C 9 2
2 Med D 3 1
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LISTAGG in Oracle to return distinct values
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19c and later:
select listagg(distinct the_column, ',') within group (order by the_column)
from the_table
18c and earlier:
select listagg(the_column, ',') within group (order by the_column)
from (
select distinct the_column
from the_table
) t
If you need more columns, something like...
Generate list of all possible permutations of a string
...nput was sorted and finding indexes (k0 and l0) itself, based on where the ordering is maintained. Sorting an input like "54321" -> "12345" would allow this algorithm to find all of the expected permutations. But since it does a good amount of extra work to re-find those indexes for every permuta...
Why use the SQL Server 2008 geography data type?
...jobsite)
where distance < 500 * 1609.344
orderby distance
select f;
return q1.FirstOrDefault();
}
Then there is a very good reason to use Geography.
Explanation of spatial within Entity Framework.
Updated with Creating High Performance Spati...
Importance of varchar length in MySQL table
... Anytime your select query uses a temporary table (group and order by operations, among other things) it will convert varchar(200) to a char(200) and performance will suffer.
– Jamie
Feb 7 '13 at 20:14
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Profiling Vim startup time
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I created this Github project in order to better answer your question. Basically, it sums up the timing for each function calls for every plugins, which is not obvious (but important) from the raw vim profile output. Bash, Python, R, Ruby are supported for c...
What are the disadvantages of using persistent connection in PDO
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I hope I had read this answer before running SELECT orders.* FROM orders LEFT JOIN items USING(item_id)
– Ast Derek
Jul 26 '10 at 18:09
31
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How to use glob() to find files recursively?
...ither way. As it stands now, it matches the "files then pattern" argument order of fnmatch.filter, which is roughly as useful as the possibility of matching single-argument glob.glob.
– Alex Martelli
Jan 4 '15 at 21:43
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