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Why use Abstract Base Classes in Python?
...lass promises to do certain things and have certain properties.
There are different levels to the contract.
At a very low level, the contract might include the name of a method or its number of parameters.
In a staticly-typed language, that contract would actually be enforced by the compiler. In Pyt...
Using unset vs. setting a variable to empty
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Mostly you don't see a difference, unless you are using set -u:
/home/user1> var=""
/home/user1> echo $var
/home/user1> set -u
/home/user1> echo $var
/home/user1> unset var
/home/user1> echo $var
-bash: var: unbound variable
S...
Why should I use 'li' instead of 'div'?
...ed, it can be helpful to distinguish what's in a list and what's not. Say if you have a list of ingredients in a recipe for example, and the user wants to skip to the instructions or just read the list, you need a list.
– Dave Markle
Feb 14 '09 at 19:57
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What are the pros and cons of performing calculations in sql vs. in your application
...that scales out; rather than a db server, which scales up)
volume of data (if you need to access/aggregate a lot of data, doing it at the db server will save bandwidth, and disk io if the aggregates can be done inside indexes)
convenience (sql is not the best language for complex work - especially n...
What will happen if I modify a Python script while it's running?
...magine a python script that will take a long time to run, what will happen if I modify it while it's running? Will the result be different?
...
Get the POST request body from HttpServletRequest
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In Java 8, you can do it in a simpler and clean way :
if ("POST".equalsIgnoreCase(request.getMethod()))
{
test = request.getReader().lines().collect(Collectors.joining(System.lineSeparator()));
}
sh...
Static class initializer in PHP
...in the class require a ‘heavy’ initialization function to run once (as if it were a constructor).
8 Answers
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C++11 range based loop: get item by value or reference to const
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If you don't want to change the items as well as want to avoid making copies, then auto const & is the correct choice:
for (auto const &x : vec)
Whoever suggests you to use auto & is wrong. Ignore them.
Here i...
How is pattern matching in Scala implemented at the bytecode level?
... explored with a disassembler but the short answer is that it's a bunch of if/elses where the predicate depends on the pattern
case Sum(l,r) // instance of check followed by fetching the two arguments and assigning to two variables l and r but see below about custom extractors
case "hello" // equa...
Wrong requestCode in onActivityResult
...this, the requestCode is changed by the Activity that owns the Fragment.
If you want to get the correct resultCode in your activity try this:
Change:
startActivityForResult(intent, 1);
To:
getActivity().startActivityForResult(intent, 1);
...