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Why does Java's hashCode() in String use 31 as a multiplier?
...iplying by 31 can be relatively cheap. On an ARM, for instance, it is only one instruction:
RSB r1, r0, r0, ASL #5 ; r1 := - r0 + (r0<<5)
Most other processors would require a separate shift and subtract instruction. However, if your multiplier is slow this is still a win. Modern p...
Concatenating two one-dimensional NumPy arrays
I have two simple one-dimensional arrays in NumPy . I should be able to concatenate them using numpy.concatenate . But I get this error for the code below:
...
Test if lists share any items in python
I want to check if any of the items in one list are present in another list. I can do it simply with the code below, but I suspect there might be a library function to do this. If not, is there a more pythonic method of achieving the same result.
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How do I make and use a Queue in Objective-C?
...ex:0];
}
return headObject;
}
// Add to the tail of the queue (no one likes it when people cut in line!)
- (void) enqueue:(id)anObject {
[self addObject:anObject];
//this method automatically adds to the end of the array
}
@end
Just import the .h file wherever you want to use your...
Angular directives - when and how to use compile, controller, pre-link and post-link [closed]
When writing an Angular directive, one can use any of the following functions to manipulate the DOM behaviour, contents and look of the element on which the directive is declared:
...
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...
Scalar vs. primitive data type - are they the same thing?
...context (and frequently what language family is being discussed). To take one, possibly pathological, example: strings. In C, a string is a compound (an array of characters), while in Perl, a string is a scalar. In Java, a string is an object (or reference type). In Python, everything is (conceptua...
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
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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.
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Copy values from one column to another in the same table
How can I make a copy values from one column to another? I have:
7 Answers
7
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