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What's the difference between Ruby's dup and clone methods?
..., name: "Favorites">
clone creates a new object with the same id, so all the changes made to that new object will overwrite the original record if hitting .save
category2 = category.clone
#=> #<Category id: 1, name: "Favorites">
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Java Name Hiding: The Hard Way
... of working with the reflection API.
The downside is that this code is really horrible! For me, it generates a warning, and that's a good thing in general. But since it's working around a problem that is otherwise thoroughly impractical, adding a
@SuppressWarnings("static-access")
at an approp...
How do I make class methods / properties in Swift?
...
They are called type properties and type methods and you use the class or static keywords.
class Foo {
var name: String? // instance property
static var all = [Foo]() // static type property
class var comp: In...
In Python, how do I iterate over a dictionary in sorted key order?
...ems() creates a list and therefore uses memory, whereas iteritems() essentially does not use memory. What to use mostly depend on the size of the dictionary. Furthermore, the automatic Python 2 to Python 3 conversion tool (2to3) automatically takes care of the conversion from iteritems() to items(),...
MySQL: selecting rows where a column is null
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NULL = NULL is not really FALSE - it's NULL again. But it's not TRUE either, so IF(NULL = NULL) won't execute.
– Konerak
Jan 12 '11 at 19:50
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Mercurial — revert back to old version and continue from there
I'm using Mercurial locally for a project (it's the only repo there's no pushing/pulling to/from anywhere else).
7 Answers
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Flask-SQLalchemy update a row's information
...e many objects to be updated.
If you want to give add_user permission to all the admins,
rows_changed = User.query.filter_by(role='admin').update(dict(permission='add_user'))
db.session.commit()
Notice that filter_by takes keyword arguments (use only one =) as opposed to filter which takes an e...
Is it possible to modify variable in python that is in outer, but not global, scope?
...a list, or dict), and mutate the value instead of reassign.
example:
def foo():
a = []
def bar():
a.append(1)
bar()
bar()
print a
foo()
Outputs:
[1, 1]
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imp...
PHP - Move a file into a different folder on the server
I need to allow users on my website to delete their images off the server after they have uploaded them if they no longer want them. I was previously using the unlink function in PHP but have since been told that this can be quite risky and a security issue. (Previous code below:)
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C# namespace alias - what's the point?
... name from different assemblies - rare, but useful to be supported.
Actually, I can see another use: when you want quick access to a type, but don't want to use a regular using because you can't import some conflicting extension methods... a bit convoluted, but... here's an example...
namespace ...