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Correct format specifier for double in printf
What is the correct format specifier for double in printf? Is it %f or is it %lf ? I believe it's %f , but I am not sure.
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NSString property: copy or retain?
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For attributes whose type is an immutable value class that conforms to the NSCopying protocol, you almost always should specify copy in your @property declaration. Specifying retain is something you almost never want in such ...
What does ||= (or-equals) mean in Ruby?
...ling-list that discuss this issue.
Here's one: The definitive list of ||= (OR Equal) threads and pages
If you really want to know what is going on, take a look at Section 11.4.2.3 "Abbreviated assignments" of the Ruby Language Draft Specification.
As a first approximation,
a ||= b
is equivalent to
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What is the difference between window, screen, and document in Javascript?
I see these terms used interchangeably as the global environment for the DOM. What is the difference (if there is one) and when should I use each one?
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Why do you need explicitly have the “self” argument in a Python method?
...cit rather than based on a rule.
Additionally, since nothing is implied or assumed, parts of the implementation are exposed. self.__class__, self.__dict__ and other "internal" structures are available in an obvious way.
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Best way of invoking getter by reflection
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I think this should point you towards the right direction:
import java.beans.*
for (PropertyDescriptor pd : Introspector.getBeanInfo(Foo.class).getPropertyDescriptors()) {
if (pd.getReadMethod() != null && !"class".equals(pd.getName()))
System.out.println(pd.getReadMethod...
When to use window.opener / window.parent / window.top
...s called
window.parent refers to the parent of a window in a <frame> or <iframe>
window.top refers to the top-most window from a window nested in one or more layers of <iframe> sub-windows
Those will be null (or maybe undefined) when they're not relevant to the referring window's...
How to get a key in a JavaScript object by its value?
... associative array. Is there a simple function allowing me to get the key for a value, or do I have to iterate the object and find it out manually?
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JavaScript check if variable exists (is defined/initialized)
Which method of checking if a variable has been initialized is better/correct?
(Assuming the variable could hold anything (string, int, object, function, etc.))
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Learning Ant path style
...e conventions? I've gone to the Ant site itself, but couldn't find any information on path styles.
5 Answers
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