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Can someone explain __all__ in Python?
...> import * is used on the module.
For example, the following code in a foo.py explicitly exports the symbols bar and baz:
__all__ = ['bar', 'baz']
waz = 5
bar = 10
def baz(): return 'baz'
These symbols can then be imported like so:
from foo import *
print(bar)
print(baz)
# The following w...
Rails where condition using NOT NIL
...
The canonical way to do this with Rails 3:
Foo.includes(:bar).where("bars.id IS NOT NULL")
ActiveRecord 4.0 and above adds where.not so you can do this:
Foo.includes(:bar).where.not('bars.id' => nil)
Foo.includes(:bar).where.not(bars: { id: nil })
When working...
Get top n records for each group of grouped results
...s can be returned, as shown below:
.headers on
.mode column
CREATE TABLE foo (person, groupname, age);
INSERT INTO foo VALUES('Paul',2,36);
INSERT INTO foo VALUES('Laura',2,39);
INSERT INTO foo VALUES('Joe',2,36);
INSERT INTO foo VALUES('Bob',1,32);
INSERT INTO foo VALUES('Jill',1,34);
INSERT INTO...
How do you normalize a file path in Bash?
I want to transform /foo/bar/.. to /foo
22 Answers
22
...
How to call a Parent Class's method from Child Class in Python?
...
Yes, but only with new-style classes. Use the super() function:
class Foo(Bar):
def baz(self, arg):
return super().baz(arg)
For python < 3, use:
class Foo(Bar):
def baz(self, arg):
return super(Foo, self).baz(arg)
...
How to initialize static variables
...ork around this by adding code right after definition of the class:
class Foo {
static $bar;
}
Foo::$bar = array(…);
or
class Foo {
private static $bar;
static function init()
{
self::$bar = array(…);
}
}
Foo::init();
PHP 5.6 can handle some expressions now.
/* For Abstrac...
ReadOnlyCollection or IEnumerable for exposing member collections?
...pe to be an immutable collection, and then expose that directly - assuming Foo itself is immutable, of course.
Updated answer to address the question more directly
Is there any reason to expose an internal collection as a ReadOnlyCollection rather than an IEnumerable if the calling code only it...
How to check if a Ruby object is a Boolean
...
Simplest way I can think of:
# checking whether foo is a boolean
!!foo == foo
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jQuery access input hidden value
...t like you can do on any other input element:
<input type="hidden" id="foo" name="zyx" value="bar" />
alert($('input#foo').val());
alert($('input[name=zyx]').val());
alert($('input[type=hidden]').val());
alert($(':hidden#foo').val());
alert($('input:hidden[name=zyx]').val());
Those all mea...
What is global::?
...used to solve problems whereby you may redefine types. For example:
class foo
{
class System
{
}
}
If you were to use System where it would be locally scoped in the foo class, you could use:
global::System.Console.WriteLine("foobar");
to access the global namespace.
Example
usi...