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Why does ConcurrentHashMap prevent null keys and values?
The JavaDoc of ConcurrentHashMap says this:
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ALTER DATABASE failed because a lock could not be placed on database
I need to restart a database because some processes are not working. My plan is to take it offline and back online again.
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What is the preferred syntax for initializing a dict: curly brace literals {} or the dict() function
I'm putting in some effort to learn Python, and I am paying close attention to common coding standards. This may seem like a pointlessly nit-picky question, but I am trying to focus on best-practices as I learn, so I don't have to unlearn any 'bad' habits.
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Select rows of a matrix that meet a condition
In R with a matrix:
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How do you make sure email you send programmatically is not automatically marked as spam?
This is a tricky one and I've always relied on techniques, such as permission-based emails (i.e. only sending to people you have permission to send to) and not using blatantly spamish terminology.
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Python 3 turn range to a list
I'm trying to make a list with numbers 1-1000 in it. Obviously this would be annoying to write/read, so I'm attempting to make a list with a range in it. In Python 2 it seems that:
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Why does Math.floor return a double?
Official Javadoc says that Math.floor() returns a double that is "equal to a mathematical integer", but then why shouldn't it return an int ?
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How to declare a variable in a PostgreSQL query
How do I declare a variable for use in a PostgreSQL 8.3 query?
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How does the Amazon Recommendation feature work?
What technology goes in behind the screens of Amazon recommendation technology? I believe that Amazon recommendation is currently the best in the market, but how do they provide us with such relevant recommendations?
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Most efficient way to prepend a value to an array
Assuming I have an array that has a size of N (where N > 0 ), is there a more efficient way of prepending to the array that would not require O(N + 1) steps?
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