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Understanding implicit in Scala
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I had the exact same question as you had and I think I should share how I started to understand it by a few really simple examples (note that it only covers the common use cases).
There are two common use cases in Scala using implicit.
Using it on a variable
Using it on a function
Examples are...
Why are Perl 5's function prototypes bad?
... most things people guess about Perl, they turn out to be wrong.
However, starting with Perl v5.20, Perl has a feature, experimental as I write this, that gives something more like what users expect and what. Perl's subroutine signatures does run time argument counting, variable assigning, and defa...
Understanding Fragment's setRetainInstance(boolean)
Starting with the documentation:
5 Answers
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No == operator found while comparing structs in C++
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Starting in C++20, it should be possible to add a full set of default comparison operators (==, <=, etc.) to a class by declaring a default three-way comparison operator ("spaceship" operator), like this:
struct Point {
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SET versus SELECT when assigning variables?
...run at once too: Example: SELECT @Int = @Int + 1, @Int = @Int + 1, if @Int started as 0, it then ends as 2. This can be very useful when doing successive string-manipulations.
– MikeTeeVee
Aug 26 '15 at 15:33
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Need to reset git branch to origin version
...e any new file or reset modified file to HEAD.
Actually, to be sure you start from a "clean slate", a git clean -f -d after the reset would ensure a working tree exactly identical to the branch you just reset to.
This blog post suggests those aliases (for master branch only, but you can adapt/...
How to send a “multipart/form-data” with requests in python?
...escribed in the section POST a Multipart-Encoded File in the requests quickstart:
>>> url = 'http://httpbin.org/post'
>>> files = {'file': ('report.xls', open('report.xls', 'rb'), 'application/vnd.ms-excel', {'Expires': '0'})}
In the above, the tuple is composed as follows:
(fi...
Why should hash functions use a prime number modulus?
...ou can only do (bucket_count / stride) probes before you're back where you started. The case you most want to avoid is stride = 0, of course, which must be special-cased, but to avoid also special-casing bucket_count / stride equal to a small integer, you can just make the bucket_count prime and not...
Git submodule head 'reference is not a tree' error
...mmit was pushed in A, but the actual commit was not pushed from B. So I'd start there.
Less likely, there's a permissions problem, and the commit cannot be pulled (possible if you're using git+ssh).
Make sure the submodule paths look ok in .git/config and .gitmodules.
One last thing to try - ins...
Using Java 8's Optional with Stream::flatMap
...tand.) However, sometimes things can be too clever. The modified code also starts off with an Optional<Other>. Then it calls Optional.map which is defined as follows:
If a value is present, apply the provided mapping function to it, and if the result is non-null, return an Optional describ...