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What does the exclamation mark do before the function?
..., when we add the seemingly innocuous exclamation mark: !function foo() {} it turns it into an expression. It is now a function expression.
The ! alone doesn't invoke the function, of course, but we can now put () at the end: !function foo() {}() which has higher precedence than ! and instantly cal...
Double not (!!) operator in PHP
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It's not the "double not operator", it's the not operator applied twice. The right ! will result in a boolean, regardless of the operand. Then the left ! will negate that boolean.
This means that for any true value (numbers...
Please explain some of Paul Graham's points on Lisp
...list seem the most interesting and still relevant now.
To understand them, it is useful to have a clear picture of what happens with Lisp code -- in the form of a stream of characters typed in by the programmer -- on its way to being executed. Let's use a concrete example:
;; a library import for co...
delete vs delete[] operators in C++
...r deallocates memory and calls the destructor for a single object created with new.
The delete [] operator deallocates memory and calls destructors for an array of objects created with new [].
Using delete on a pointer returned by new [] or delete [] on a pointer returned by new results in undefin...
Tab Vs Space preferences in Vim
Vim is very accommodating when it comes to tab Vs. space preferences. As I understand it, the tabstop setting indicates the width of a tab character. The shiftwidth setting specifies how many columns to increment/decrement when using the << and >> commands, whereas the softtabst...
Tools to selectively Copy HTML+CSS+JS From A Specific Element of DOM [closed]
Like most web developers, I occasionally like to look at the source of websites to see how their markup is built. Tools like Firebug and Chrome Developer Tools make it easy to inspect the code, but if I want to copy a specific section and play around with it locally, it would be a pain to copy all t...
Are there any reasons to use private properties in C#?
I just realized that the C# property construct can also be used with a private access modifier:
16 Answers
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Current location permission dialog disappears too quickly
...t view that asks for the users location appears then disappears so quickly it's impossible to click it!
12 Answers
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When do I use fabs and when is it sufficient to use std::abs?
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In C++, it's always sufficient to use std::abs; it's overloaded for all the numerical types.
In C, abs only works on integers, and you need fabs for floating point values. These are available in C++ (along with all of the C library...
How to change font of UIButton with Swift
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Use titleLabel instead. The font property is deprecated in iOS 3.0. It also does not work in Objective-C. titleLabel is label used for showing title on UIButton.
myButton.titleLabel?.font = UIFont(name: YourfontName, size: 20)
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