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async/await - when to return a Task vs void?
...sk. The main exception should be when you need to have a void return type (for events). If there's no reason to disallow having the caller await your task, why disallow it?
2) async methods that return void are special in another aspect: they represent top-level async operations, and have additiona...
What is a sealed trait?
...l of its subclasses are declared within the
same file and that makes the set of subclasses finite which allows
certain compiler checks.
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When should I use genetic algorithms as opposed to neural networks? [closed]
Is there a rule of thumb (or set of examples) to determine when to use genetic algorithms as opposed to neural networks (and vice-versa) to solve a problem?
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What is the difference between bottom-up and top-down?
...97 linked a dynamic programming example of finding the maximum independent set in a tree, which corresponds to filling in the blanks in a tree.
(At it's most general, in a "dynamic programming" paradigm, I would say the programmer considers the whole tree, then writes an algorithm that implements...
JavaScript string newline character?
...s, and Firefox 3.0 on Linux) use \n. They can all handle \n just fine when setting the value, though IE and Opera will convert that back to \r\n again internally. There's a SitePoint article with some more details called Line endings in Javascript.
Note also that this is independent of the actual l...
How to find patterns across multiple lines using grep?
...P Use perl compatible regular expressions (PCRE).
-z Treat the input as a set of lines, each terminated by a zero byte instead of a newline. i.e. grep treats the input as a one big line.
-l list matching filenames only.
(?s) activate PCRE_DOTALL, which means that '.' finds any character or newlin...
How do I find the duplicates in a list and create another list with them?
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To remove duplicates use set(a). To print duplicates, something like:
a = [1,2,3,2,1,5,6,5,5,5]
import collections
print([item for item, count in collections.Counter(a).items() if count > 1])
## [1, 2, 5]
Note that Counter is not particularly...
What is an “unwrapped value” in Swift?
...at the second two cases will give you a runtime error if optionalSquare is set to nil. Using the syntax in the first case, you can do something like this:
if let sideLength = optionalSquare?.sideLength {
println("sideLength is not nil")
} else {
println("sidelength is nil")
}
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Python - How to sort a list of lists by the fourth element in each list? [duplicate]
I would like to sort the following list of lists by the fourth element (the integer) in each individual list.
2 Answers
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How can I get the console logs from the iOS Simulator?
I want to see what happens in the iOS Simulator if I'm not testing the app in Xcode.
12 Answers
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