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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...
What is a stream?
What is a stream in the programming world? Why do we need it?
6 Answers
6
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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...
&& (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 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...
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 an idempotent operation?
What is an idempotent operation?
15 Answers
15
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Which is the preferred way to concatenate a string in Python?
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The best way of appending a string to a string variable is to use + or +=. This is because it's readable and fast. They are also just as fast, which one you choose is a matter of taste, the latter one is the most common. Here are timings with the timeit module:
a = a + b:
0.11338...