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Odd behavior when Java converts int to byte?
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132 in digits (base 10) is 1000_0100 in bits (base 2) and Java stores int in 32 bits:
0000_0000_0000_0000_0000_0000_1000_0100
Algorithm for int-to-byte is left-truncate; Algorithm for System.out.println is two's-complement (Two's-complement is if leftmos...
How to use PyCharm to debug Scrapy projects
... a virtualenv with Python 3.5.0 and setting the "script" parameter to /path_to_project_env/env/bin/scrapy solved the issue for me.
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Is cout synchronized/thread-safe?
... @ildjarn - No, @edA-qa mort-ora-y is correct. As long as cout.sync_with_stdio() is true, using cout to output characters from multiple threads without additional synchronization is well-defined, but only on the level of individual bytes. Thus, cout << "ab"; and cout << "cd" exec...
if A vs if A is not None:
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The statement
if A:
will call A.__nonzero__() (see Special method names documentation) and use the return value of that function. Here's the summary:
object.__nonzero__(self)
Called to implement truth value testing and the built-in operation bool()...
How do you echo a 4-digit Unicode character in Bash?
... That's true. I discovered i was using LANG=C instead of LANG=en_US.UTF-8. Now my terminals in Gnome show the symbols properly... The real terminals (tty1-6) still don't though.
– trusktr
Oct 3 '12 at 0:09
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Is there a way to instantiate objects from a string holding their class name?
...ce() { return new T; }
typedef std::map<std::string, Base*(*)()> map_type;
map_type map;
map["DerivedA"] = &createInstance<DerivedA>;
map["DerivedB"] = &createInstance<DerivedB>;
And then you can do
return map[some_string]();
Getting a new instance. Another idea is ...
Check if object is file-like in Python
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why what about operators like __add__, __lshift__ or __or__ in custom classes? (file object and API: docs.python.org/glossary.html#term-file-object )
– n611x007
Sep 8 '12 at 12:56
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What do (lambda) function closures capture?
...ere for what dynamic scope really is: voidspace.org.uk/python/articles/code_blocks.shtml .
– Claudiu
Jun 29 '10 at 15:21
6
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Printf width specifier to maintain precision of floating-point value
...be to print one seventh as in:
#include <float.h>
int Digs = DECIMAL_DIG;
double OneSeventh = 1.0/7.0;
printf("%.*e\n", Digs, OneSeventh);
// 1.428571428571428492127e-01
But let's dig deeper ...
Mathematically, the answer is "0.142857 142857 142857 ...", but we are using finite precision...
How do I search for an object by its ObjectId in the mongo console?
...est.find() // no criteria
{ "_id" : ObjectId("4ecc05e55dd98a436ddcc47c"), "x" : 1 }
> db.test.find({"_id" : ObjectId("4ecc05e55dd98a436ddcc47c")}) // explicit
{ "_id" : ObjectId("4ecc05e55dd98a436ddcc47c"), "x" : 1 }
> db.test.find(ObjectId...