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How to express a NOT IN query with ActiveRecord/Rails?
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edited Feb 1 at 13:08
notapatch
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answered ...
Java Singleton and Synchronization
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edited Apr 20 '17 at 13:48
mfb
8031010 silver badges1414 bronze badges
answered Jun 23 '12...
send mail from linux terminal in one line [closed]
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answered Dec 2 '13 at 0:02
PSkocikPSkocik
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Why are arrays covariant but generics are invariant?
...nimals = dogs; // Awooga awooga
animals.add(new Cat());
Dog dog = dogs.get(0); // This should be safe, right?
Suddenly you have a very confused cat.
The original motivation for making arrays covariant described in the wikipedia article didn't apply to generics because wildcards made the expr...
Vagrant error : Failed to mount folders in Linux guest
...have some issues with Vagrant shared folders, my base system is Ubuntu 13.10 desktop.
21 Answers
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How to determine if a record is just created or updated in after_save
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edited Nov 10 '17 at 19:39
answered Aug 25 '11 at 0:41
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Regex - Should hyphens be escaped? [duplicate]
...lace a hyphen as the first or last character in the range (e.g. [-a-z] or [0-9-]), OR escape it (e.g. [a-z\-0-9]) in order to add "hyphen" to your class.
It's more common to find a hyphen placed first or last within a character class, but by no means will you be lynched by hordes of furious neckbea...
Unmangling the result of std::type_info::name
...e, NULL, NULL, &status),
std::free
};
return (status==0) ? res.get() : name ;
}
#else
// does nothing if not g++
std::string demangle(const char* name) {
return name;
}
#endif
Usage:
#include <iostream>
#include "type.hpp"
struct Base { virtual ~Base() {} };
st...
Mimicking sets in JavaScript?
... ES6: The current working version of ECMAScript 6 or somethings called ES 2015 has a built-in Set object. It is implemented now in some browsers. Since browser availability changes over time, you can look at the line for Set in this ES6 compatibility table to see the current status for browser ava...
How to write log to file
..., err := os.OpenFile("testlogfile", os.O_RDWR | os.O_CREATE | os.O_APPEND, 0666)
if err != nil {
log.Fatalf("error opening file: %v", err)
}
defer f.Close()
log.SetOutput(f)
log.Println("This is a test log entry")
Based on the Go docs, os.Open() can't work for log.SetOutput, because it opens ...