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Create singleton using GCD's dispatch_once in Objective-C
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This is a perfectly acceptable and thread-safe way to create an instance of your class. It may not technically be a "singleton" (in that there can only ever be 1 of these objects), but as long as you only use the [Foo sharedFoo] metho...
Why does Ruby have both private and protected methods?
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protected methods can be called by any instance of the defining class or its subclasses.
private methods can be called only from within the calling object. You cannot access another instance's private methods directly.
Her...
Java: is there a map function?
I need a map function. Is there something like this in Java already?
6 Answers
6
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In which order do CSS stylesheets override?
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The rules for CSS rule cascading are complex -- rather than trying to paraphrase them badly, I'll simply refer you to the spec:
http://www.w3.org/TR/2011/REC-CSS2-20110607/cascade.html#cascade
In short: more specific rules override more general ones. Specificity ...
ValueError : I/O operation on closed file
Here, p is a dictionary, w and c both are strings.
2 Answers
2
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How can I view all historical changes to a file in SVN
I know that I can svn diff -r a:b repo to view the changes between the two specified revisions. What I'd like is a diff for every revision that changed the file. Is such a command available?
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How to vertically align text inside a flexbox?
...th one adjustment, to make it all work:
ul {
height: 100%;
}
li {
display: flex;
justify-content: center;
/* align-self: center; <---- REMOVE */
align-items: center; /* <---- NEW */
background: silver;
width: 100%;
height: 20%;
}
The align-self property applies to ...
How to “crop” a rectangular image into a square with CSS?
I know that it is impossible to actually modify an image with CSS, which is why I put crop in quotes.
10 Answers
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How can I run an external command asynchronously from Python?
I need to run a shell command asynchronously from a Python script. By this I mean that I want my Python script to continue running while the external command goes off and does whatever it needs to do.
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'const int' vs. 'int const' as function parameters in C++ and C
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const T and T const are identical. With pointer types it becomes more complicated:
const char* is a pointer to a constant char
char const* is a pointer to a constant char
char* const is a constant pointer to a (mutable) char
In other words, (1) and (2) are iden...