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SBT stop run without exiting
...you can't easily kill them separately.
If you do your run in a separate, forked JVM, as described at Forking, then you can kill that JVM (by any means your operating system offers) without affecting sbt's JVM:
fork in run := true
...
Run a callback only if an attribute has changed in Rails
...
Rails 5.1+
class Page < ActiveRecord::Base
before_save :do_something, if: :will_save_change_to_status_id?
private
def do_something
# ...
end
end
The commit that changed ActiveRecord::Dirty is here: https://github.com/rails/rails/commit/16ae3d...
How to prevent multiple instances of an Activity when it is launched with different Intents
...ication when it is launched using the "Open" button on the Google Play Store app (previously called Android Market). It seems that launching it from the Play Store uses a different Intent than launching it from the phone's application menu of icons. This is leading to multiple copies of the same...
Renaming table in rails
...
You would typically do this sort of thing in a migration:
class RenameFoo < ActiveRecord::Migration
def self.up
rename_table :foo, :bar
end
def self.down
rename_table :bar, :foo
end
end
...
Why sizeof int is wrong, while sizeof(int) is right?
We know that sizeof is an operator used for calculating the size of any datatype and expression, and when the operand is an expression, the parentheses can be omitted.
...
How to get element by class name? [duplicate]
...ctually getElementsByClassName, not getElementByClassName, simply because more than one element on the page can have the same class, hence: Elements.
The return value of this will be a NodeList instance, or a superset of the NodeList (FF, for instance returns an instance of HTMLCollection). At any ...
Is there a difference between “==” and “is”?
...gt;>> b == a
True
# Make a new copy of list `a` via the slice operator,
# and assign it to variable `b`
>>> b = a[:]
>>> b is a
False
>>> b == a
True
In your case, the second test only works because Python caches small integer objects, which is an implementation...
When to throw an exception?
I have exceptions created for every condition that my application does not expect. UserNameNotValidException , PasswordNotCorrectException etc.
...
How to check if an app is installed from a web-page on an iPhone?
...ant to create a web-page, a page that will redirect an iPhone to the app-store if the iPhone does not have the application installed, but if the iPhone has the app installed I want it to open the application.
...
Valid to use (anchor tag) without href attribute?
...
The <a>nchor element is simply an anchor to or from some content. Originally the HTML specification allowed for named anchors (<a name="foo">) and linked anchors (<a href="#foo">).
The named anchor format is less commonly ...