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Is there a “null coalescing” operator in JavaScript?
...an results in false, the assignment will use the second operand. Beware of all the cases below:
alert(Boolean(null)); // false
alert(Boolean(undefined)); // false
alert(Boolean(0)); // false
alert(Boolean("")); // false
alert(Boolean("false")); // true -- gotcha! :)
This means:
var whatIWant = n...
How to do the equivalent of pass by reference for primitives in Java
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You have several choices. The one that makes the most sense really depends on what you're trying to do.
Choice 1: make toyNumber a public member variable in a class
class MyToy {
public int toyNumber;
}
then pass a reference to a MyToy to your method.
void play(MyToy toy){
...
What is the difference between related SQLite data-types like INT, INTEGER, SMALLINT and TINYINT?
When creating a table in SQLite3, I get confused when confronted with all the possible datatypes which imply similar contents, so could anyone tell me the difference between the following data-types?
...
Django auto_now and auto_now_add
... change between every release. (Which I believe is the impetus behind the call to have them removed altogether).
The fact that they only work on DateField, DateTimeField, and TimeField, and by using this technique you are able to automatically populate any field type every time an item is saved.
Use...
undefined reference to `WinMain@16'
...
Building without that semi-documented flag one would have to more specifically tell the linker which subsystem value one desires, and some Windows API import libraries will then in general have to be specified explicitly:
C:\test> gnuc x.cpp -Wl,-subsystem,windows
C:\test> objdump -x a.exe...
Difference between single and double square brackets in Bash
...nt of [ that prevents further arguments from being used.
Ubuntu 16.04 actually has an executable for it at /usr/bin/[ provided by coreutils, but the bash built-in version takes precedence.
Nothing is altered in the way that Bash parses the command.
In particular, < is redirection, && a...
How to automatically install Emacs packages by specifying a list of package names?
...a list of package names in .emacs file and then package could automatically search and install the packages, so that I don't need to install them manually by calling M-x package-list-packages . How to do that?
...
How to use a servlet filter in Java to change an incoming servlet request url?
... a check in the code if the URL needs to be changed and if not, then just call FilterChain#doFilter(), else it will call itself in an infinite loop.
Alternatively you can also just use an existing 3rd party API to do all the work for you, such as Tuckey's UrlRewriteFilter which can be configured th...
Using python's eval() vs. ast.literal_eval()?
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datamap = eval(raw_input('Provide some data here: ')) means that you actually evaluate the code before you deem it to be unsafe or not. It evaluates the code as soon as the function is called. See also the dangers of eval.
ast.literal_eval raises an exception if the input isn't a valid Python dat...
How can I produce an effect similar to the iOS 7 blur view?
...backgroundColor = [UIColor clearColor];
UIToolbar* bgToolbar = [[UIToolbar alloc] initWithFrame:myView.frame];
bgToolbar.barStyle = UIBarStyleDefault;
[myView.superview insertSubview:bgToolbar belowSubview:myView];
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