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How do you check if a variable is an array in JavaScript? [duplicate]
...ys of checking if an variable is an array or not. The best solution is the one you have chosen.
variable.constructor === Array
This is the fastest method on Chrome, and most likely all other browsers. All arrays are objects, so checking the constructor property is a fast process for JavaScript en...
How do I remove duplicate items from an array in Perl?
...q4:
sub uniq {
my %seen;
grep !$seen{$_}++, @_;
}
my @array = qw(one two three two three);
my @filtered = uniq(@array);
print "@filtered\n";
Outputs:
one two three
If you want to use a module, try the uniq function from List::MoreUtils
...
Convert seconds to HH-MM-SS with JavaScript?
... better as pointed out by T.J. Crowder.
--update 2
Please use @Frank's a one line solution:
new Date(SECONDS * 1000).toISOString().substr(11, 8)
It is by far the best solution.
share
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improve ...
Using Gradle to build a jar with dependencies
I have a multiproject build and I put a task to build a fat jar in one of the subprojects. I created the task similar to the one described in the cookbook .
...
How to search and replace globally, starting from the cursor position and wrapping around the end of
...t, the substitution command is run for each line starting from
the current one until the end of file:
,$s/BEFORE/AFTER/gc
Then, that :substitute command is repeated with the same search
pattern, replacement string, and flags, using the :& command
(see :help :&):
1,''-&&
The latter...
What is the copy-and-swap idiom?
...ent operator is arguably the most nuanced and difficult. How should it be done? What pitfalls need to be avoided?
The copy-and-swap idiom is the solution, and elegantly assists the assignment operator in achieving two things: avoiding code duplication, and providing a strong exception guarantee.
H...
OpenID vs. OAuth [duplicate]
...
OpenID is a way to specify one identity for multiple sites so you don't need to register over and over again.
OAuth is a way to allow one application access to one account without giving said application your account login information. You can use th...
How to choose an AES encryption mode (CBC ECB CTR OCB CFB)?
...
ECB should not be used if encrypting more than one block of data with the same key.
CBC, OFB and CFB are similar, however OFB/CFB is better because you only need encryption and not decryption, which can save code space.
CTR is used if you want good parallelization (ie. sp...
How to remove an item for a OR'd enum?
... (&) with some value (let's call that value 'X') and the complement of one or more set bits (let's call those bits Q and their complement ~Q), the statement X & ~Q clears any bits that were set in Q from X and returns the result.
So to remove or clear the BLUE bits, you use the following st...
return, return None, and no return at all?
...
On the actual behavior, there is no difference. They all return None and that's it. However, there is a time and place for all of these.
The following instructions are basically how the different methods should be used (or at least how I was taught they should be used), but they are not a...