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Scala best way of turning a Collection into a Map-by-key?
If I have a collection c of type T and there is a property p on T (of type P , say), what is the best way to do a map-by-extracting-key ?
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What is the purpose of Node.js module.exports and how do you use it?
What is the purpose of Node.js module.exports and how do you use it?
12 Answers
12
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How is the default submit button on an HTML form determined?
If a form is submitted but not by any specific button, such as
14 Answers
14
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What does the “map” method do in Ruby?
...lement, outputting each returned value from the block (the original object is unchanged unless you use map!):
[1, 2, 3].map { |n| n * n } #=> [1, 4, 9]
Array and Range are enumerable types. map with a block returns an Array. map! mutates the original array.
Where is this helpful, and what is...
Getting current device language in iOS?
I'd like to show the current language that the device UI is using. What code would I use?
31 Answers
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How to declare std::unique_ptr and what is the use of it?
I try to understand how std::unique_ptr works and for that I found this document. The author starts from the following example:
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Persist javascript variables across pages? [duplicate]
Is there a way we can persist javascript variables across various pages? Suppose in Page A I am setting window.someVar = 5 . Then I move to Page B, via clicking a hyperlink in A, and do something like alert(window.someVar) -- I should get a message box displaying 5. Is there a technique to persis...
Hash Code and Checksum - what's the difference?
My understanding is that a hash code and checksum are similar things - a numeric value, computed for a block of data, that is relatively unique.
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Why do we need Abstract factory design pattern?
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Abstract Factory is a very central design pattern for Dependency Injection (DI). Here's a list of Stack Overflow questions where application of Abstract Factory has been accepted as the solution.
To the best of my understanding, these questi...
How do I pass multiple parameters into a function in PowerShell?
...nd will cause a parse error in PowerShell 2.0 (or later) if Set-StrictMode is active. Parenthesised arguments are used in .NET methods only.
function foo($a, $b, $c) {
"a: $a; b: $b; c: $c"
}
ps> foo 1 2 3
a: 1; b: 2; c: 3
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