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What's the difference between equal?, eql?, ===, and ==?
...t to try these out for yourself on different objects, use something like this:
class Object
def all_equals(o)
ops = [:==, :===, :eql?, :equal?]
Hash[ops.map(&:to_s).zip(ops.map {|s| send(s, o) })]
end
end
"a".all_equals "a" # => {"=="=>true, "==="=>true, "eql?"=>true, "e...
Does PHP have threading?
I found this PECL package called threads , but there is not a release yet. And nothing is coming up on the PHP website.
13...
What is a stream?
What is a stream in the programming world? Why do we need it?
6 Answers
6
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What is a NullPointerException, and how do I fix it?
...e where you declare a variable of primitive type int:
int x;
x = 10;
In this example, the variable x is an int and Java will initialize it to 0 for you. When you assign it the value of 10 on the second line, your value of 10 is written into the memory location referred to by x.
But, when you try to...
&& (AND) and || (OR) in IF statements
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No, it will not be evaluated. And this is very useful. For example, if you need to test whether a String is not null or empty, you can write:
if (str != null && !str.isEmpty()) {
doSomethingWith(str.charAt(0));
}
or, the other way around
if (str =...
What is the instanceof operator in JavaScript?
The instanceof keyword in JavaScript can be quite confusing when it is first encountered, as people tend to think that JavaScript is not an object-oriented programming language.
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Explicitly calling return in a function or not
...ommending a user to explicitly calling return at the end of a function (his comment was deleted though):
9 Answers
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Why is processing a sorted array faster than processing an unsorted array?
Here is a piece of C++ code that shows some very peculiar behavior. For some strange reason, sorting the data miraculously makes the code almost six times faster:
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What is a plain English explanation of “Big O” notation?
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Quick note, this is almost certainly confusing Big O notation (which is an upper bound) with Theta notation "Θ" (which is a two-side bound). In my experience, this is actually typical of discussions in non-academic settings. Apologies for...
What is an idempotent operation?
What is an idempotent operation?
15 Answers
15
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