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Convert column classes in data.table
I have a problem using data.table: How do I convert column classes? Here is a simple example: With data.frame I don't have a problem converting it, with data.table I just don't know how:
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The simplest possible JavaScript countdown timer? [closed]
Just wanted to ask how to create the simplest possible countdown timer.
3 Answers
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How do I horizontally center an absolute positioned element inside a 100% width div? [duplicate]
In the example below, #logo is positioned absolutely and I need it to be horizontally centered within #header . Normally, I would do a margin:0 auto for relatively positioned elements but I am stuck here. Can someone show me the way?
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C++ performance challenge: integer to std::string conversion
Can anyone beat the performance of my integer to std::string code, linked below?
13 Answers
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Which SQL query is faster? Filter on Join criteria or Where clause?
Compare these 2 queries. Is it faster to put the filter on the join criteria or in the WHERE clause. I have always felt that it is faster on the join criteria because it reduces the result set at the soonest possible moment, but I don't know for sure.
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How to check with javascript if connection is local host?
I want to have a check in my javascript if the page loading up is on my local machine.
12 Answers
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Floating point vs integer calculations on modern hardware
I am doing some performance critical work in C++, and we are currently using integer calculations for problems that are inherently floating point because "its faster". This causes a whole lot of annoying problems and adds a lot of annoying code.
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What are differences between AssemblyVersion, AssemblyFileVersion and AssemblyInformationalVersion?
There are three assembly version attributes. What are differences? Is it ok if I use AssemblyVersion and ignore the rest?
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Why does Decimal.Divide(int, int) work, but not (int / int)?
How come dividing two 32 bit int numbers as ( int / int ) returns to me 0 , but if I use Decimal.Divide() I get the correct answer? I'm by no means a c# guy.
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How do I catch a numpy warning like it's an exception (not just for testing)?
I have to make a Lagrange polynomial in Python for a project I'm doing. I'm doing a barycentric style one to avoid using an explicit for-loop as opposed to a Newton's divided difference style one. The problem I have is that I need to catch a division by zero, but Python (or maybe numpy) just makes i...