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How do I avoid capturing self in blocks when implementing an API?
...ied inside the block (we're not doing that) but also they are not automatically retained when the block is retained (unless you are using ARC). If you do this, you must be sure that nothing else is going to try to execute the block after the MyDataProcessor instance is released. (Given the structure...
How do I perform the SQL Join equivalent in MongoDB?
...rect. The new $lookup operator added to the aggregation pipeline is essentially identical to a left outer join:
https://docs.mongodb.org/master/reference/operator/aggregation/lookup/#pipe._S_lookup
From the docs:
{
$lookup:
{
from: <collection to join>,
localField: <...
Matplotlib plots: removing axis, legends and white spaces
...ite the resulting image, without using axes, labels, titles or anything usually automatically added by matplotlib. Here is what I did:
...
Why prefer two's complement over sign-and-magnitude for signed numbers?
...o add them.
Two's complement addition is very simple. You add numbers normally and any carry bit at the end is discarded. So they're added as follows:
0010
+ 1111
=10001
= 0001 (discard the carry)
0001 is 1, which is the expected result of "2+(-1)".
But in your "intuitive" method, adding is m...
How exactly does __attribute__((constructor)) work?
...
It runs when a shared library is loaded, typically during program startup.
That's how all GCC attributes are; presumably to distinguish them from function calls.
GCC-specific syntax.
Yes, this works in C and C++.
No, the function does not need to be static.
The destructo...
SQLite error 'attempt to write a readonly database' during insert?
...
Also, SELinux (if installed) must not be enforcing. Took me a day and a half to figure that one out.
– Steve V.
Dec 19 '10 at 8:31
...
ant warning: “'includeantruntime' was not set”
...classpath; defaults
to yes, unless build.sysclasspath is
set. It is usually best to set this to
false so the script's behavior is not
sensitive to the environment in which
it is run.
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Group query results by month and year in postgresql
...he "date" attribute.
sum("Sales") as "Sales" : The SUM() function adds up all the "Sales" values, and supplies a case-sensitive alias, with the case sensitivity maintained by using double-quotes.
group by 1,2 : The GROUP BY function must contain all columns from the SELECT list that are not part o...
How to tell if a JavaScript function is defined
...
typeof callback === "function"
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Why doesn't java.lang.Number implement Comparable? [duplicate]
...2 += 0.1d;
}
System.out.println(d2 - d1);
and you'll be left with some small difference.
So back to the issue of making Number Comparable. How would you implement it? Using something like doubleValue() wouldn't do it reliably. Remember the Number subtypes are:
Byte;
Short;
Integer;
Long;
Ato...