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Union Vs Concat in Linq
...mpare references of items. Your items have different references, thus they all are considered different. When you cast to base type X, reference is not changed.
If you will override Equals and GetHashCode (used to select distinct items), then items will not be compared by reference:
class X
{
...
Java8: Why is it forbidden to define a default method for a method from java.lang.Object
...bviously a good idea" until you start digging and you realize that its actually a bad idea.
This mail has a lot on the subject (and on other subjects too.) There were several design forces that converged to bring us to the current design:
The desire to keep the inheritance model simple;
The ...
Which iomanip manipulators are 'sticky'?
... the comments below:
By Martin:
@Chareles: Then by this requirement all manipulators are sticky. Except setw which seems to be reset after use.
By Charles:
Exactly! and the only reason that setw appears to behave differently is because there are requirements on formatted output operat...
Ignoring time zones altogether in Rails and PostgreSQL
...time zone.
timestamptz is the preferred type in the date/time family, literally. It has typispreferred set in pg_type, which can be relevant:
Generating time series between two dates in PostgreSQL
Internal storage and epoch
Internally, timestamps occupy 8 bytes of storage on disk and in RAM. It is...
Difference between Observer, Pub/Sub, and Data Binding
...
Here's my take on the three:
Data Binding
Essentially, at the core this just means "the value of property X on object Y is semantically bound to the value of property A on object B. No assumptions are made as to how Y knows or is fed changes on object B.
Observer, or Obser...
Why does the lock object have to be static?
...ons. And in the latter, there are better ways of doing it anyway.
So it really depends: how is Locker used in your scenario? Is it protecting something that is itself static? If so, the lock should be static. If it is protecting something that is instance based, then IMO the lock should also be ins...
What does “Mass Assignment” mean in Laravel?
...
Mass assignment is when you send an array to the model creation, basically setting a bunch of fields on the model in a single go, rather than one by one, something like:
$user = new User(request()->all());
(This is instead of explicitly setting each value on the model separately.)
You c...
Fastest way to check if a file exist using standard C++/C++11/C?
...e thousands of files and before doing something on them I need to check if all of them exist. What can I write instead of /* SOMETHING */ in the following function?
...
Resync git repo with new .gitignore file
... in ".gitignore file not ignoring" is a bit extreme, but should work:
# rm all files
git rm -r --cached .
# add all files as per new .gitignore
git add .
# now, commit for new .gitignore to apply
git commit -m ".gitignore is now working"
(make sure to commit first your changes you want to keep, to ...
GCC -g vs -g3 GDB Flag: What is the Difference?
...
format if neither of those are supported), including GDB extensions if
at all possible.
-gvmslevel
Request debugging information and also use level to specify how much information. The default level is 2. Level 0 produces no
debug information at all. Thus, -g0 negates -g.
....
Level 3 includes e...