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How can I check whether an array is null / empty?
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There's a key difference between a null array and an empty array. This is a test for null.
int arr[] = null;
if (arr == null) {
System.out.println("array is null");
}
"Empty" here has no official meaning. I'm choosing to define empty a...
Ruby, !! operator (a/k/a the double-bang) [duplicate]
...y, the only two things that evaluate to false are false (itself) and nil.
If you negate something, that forces a boolean context. Of course, it also negates it. If you double-negate it, it forces the boolean context, but returns the proper boolean value.
For example:
"hello" #-> this is a s...
What are the rules for calling the superclass constructor?
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Base class constructors are automatically called for you if they have no argument. If you want to call a superclass constructor with an argument, you must use the subclass's constructor initialization list. Unlike Java, C++ supports multiple inheritance (for better or worse), so ...
Coding Practices which enable the compiler/optimizer to make a faster program
...his can be a huge help for getting around aliasing slowdowns. For example, if your code looks like
void DoSomething(const Foo& foo1, const Foo* foo2, int numFoo, Foo& barOut)
{
for (int i=0; i<numFoo, i++)
{
barOut.munge(foo1, foo2[i]);
}
}
the compiler doesn't kno...
Can you have if-then-else logic in SQL? [duplicate]
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You can make the following sql query
IF ((SELECT COUNT(*) FROM table1 WHERE project = 1) > 0)
SELECT product, price FROM table1 WHERE project = 1
ELSE IF ((SELECT COUNT(*) FROM table1 WHERE project = 2) > 0)
SELECT product, price FROM table1 WHER...
AngularJS : Why ng-bind is better than {{}} in angular?
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If you are not using ng-bind, instead something like this:
<div>
Hello, {{user.name}}
</div>
you might see the actual Hello, {{user.name}} for a second before user.name is resolved (before the data is loaded)...
Syntax for if/else condition in SCSS mixin
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You could try this:
$width:auto;
@mixin clearfix($width) {
@if $width == 'auto' {
// if width is not passed, or empty do this
} @else {
display: inline-block;
width: $width;
}
}
I'm not sure of your intended result, but setting a default value should retu...
python: How do I know what type of exception occurred?
...y, it's so that you don't hide:
the fact that an error occurred
the specifics of the error that occurred (error hiding antipattern)
So as long as you take care to do none of those things, it's OK to catch the generic exception. For instance, you could provide information about the exception to ...
Type definition in object literal in TypeScript
...n object literal, not an class object. Also an interface can have methods. If your interface defines a method, then the object literal must also define it - it won't be null. The object literal must fulfill everything the the interface defines or the type system will show an error.
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How do I stop a web page from scrolling to the top when a link is clicked that triggers JavaScript?
...l the .preventDefault() method of the event object passed to your handler. If you're using jQuery to bind your handlers, that event will be an instance of jQuery.Event and it will be the jQuery version of .preventDefault(). If you're using addEventListener to bind your handlers, it will be an Event ...