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Easiest way to check for an index or a key in an array?
... associative array)
[ ${array[key]+abc} ] && echo "exists"
Basically what ${array[key]+abc} does is
if array[key] is set, return abc
if array[key] is not set, return nothing
References:
See Parameter Expansion in Bash manual and the little note
if the colon is omitted, the ope...
What are the main disadvantages of Java Server Faces 2.0?
...ts which seem to make development much faster than with ASP.NET MVC, especially on AJAX-heavy sites. Integration testing looked very nice too.
...
Benefits of prototypal inheritance over classical?
So I finally stopped dragging my feet all these years and decided to learn JavaScript "properly". One of the most head-scratching elements of the languages design is it's implementation of inheritance. Having experience in Ruby, I was really happy to see closures and dynamic typing; but for the li...
Add a space (“ ”) after an element using :after
...` \0020` as a separate answer because some fonts, eg Font Awesome will not allow \00A0 to display a space, and if you want a space between elements rather than before or after you can't use padding
– Mousey
Oct 15 '15 at 23:02
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PHP parse/syntax errors; and how to solve them
...as T_STRING explains which symbol the parser/tokenizer couldn't process finally. This isn't necessarily the cause of the syntax mistake, however.
It's important to look into previous code lines as well. Often syntax errors are just mishaps that happened earlier. The error line number is just where ...
What is the motivation for bringing Symbols to ES6?
...
Most languages (all mainstream ones afaik) provide some mechanism, usually reflection, to get access to private anyway.
– Esailija
May 14 '14 at 10:58
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What is the difference between self-types and trait subclasses?
...is extended, then you're required to mix-in an A.
When a concrete class finally extends/mixes-in these traits, some class/trait must implement A.
Consider the following examples:
scala> trait User { def name: String }
defined trait User
scala> trait Tweeter {
| user: User =>
...
What is a stack trace, and how can I use it to debug my application errors?
...
In simple terms, a stack trace is a list of the method calls that the application was in the middle of when an Exception was thrown.
Simple Example
With the example given in the question, we can determine exactly where the exception was thrown in the application. Let's have a lo...
How expensive is RTTI?
...where I've looked just says that "RTTI is expensive," but none of them actually give any benchmarks or quantitative data reguarding memory, processor time, or speed.
...
Pointers vs. values in parameters and return values
... function values, and interface values are implemented with pointers internally, and a pointer to them is often redundant.
Elsewhere, use pointers for big structs or structs you'll have to change, and otherwise pass values, because getting things changed by surprise via a pointer is confusing.
O...