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Pros and cons of Java rules engines [closed]
...and Drools?
Use a rule engine if you need to separate the business rules from the application logic. The Does Your Project Need a Rule Engine article has a good example:
For example, a typical storefront
system might involve code to calculate
a discount:
if (product.quantity > 100 &...
How to debug .htaccess RewriteRule not working
...st every rewritelog detail.
UPDATE
Things have changed in Apache 2.4:
FROM Upgrading to 2.4 from 2.2
The RewriteLog and RewriteLogLevel directives have been removed. This functionality is now provided by configuring the appropriate level of logging for the mod_rewrite module using the LogLe...
String concatenation vs. string substitution in Python
...rflow.com/questions/1000'
>>> t1 = timeit.Timer('so_q_sub(1000)','from __main__ import so_q_sub')
>>> t2 = timeit.Timer('so_q_cat(1000)','from __main__ import so_q_cat')
>>> t1.timeit(number=10000000)
12.166618871951641
>>> t2.timeit(number=10000000)
5.78139721668...
Better naming in Tuple classes than “Item1”, “Item2”
...t first, int second)>. I had to download the System.ValueTuple package from NuGet to get it to work in Visual Studio 2017.
– Matt Davis
Mar 25 '17 at 23:19
18
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How to articulate the difference between asynchronous and parallel programming?
...ender the animation takes a long time so if you were to launch that render from within your animation editing software you would make sure it was running asynchronously so it didn't lock up your UI and you could continue doing other things. Now, each frame of that animation can also be considered as...
Negative weights using Dijkstra's Algorithm
...neral. For example, consider this graph:
Assume the edges are directed from left to right as in your example,
Your algorithm will work as follows:
First, you set d(A) to zero and the other distances to infinity.
You then expand out node A, setting d(B) to 1, d(C) to zero, and d(D) to 99.
Nex...
Why does Apple recommend to use dispatch_once for implementing the singleton pattern under ARC?
... it's faster. It's also semantically cleaner, because it also protects you from multiple threads doing alloc init of your sharedInstance--if they all try at the same exact time. It won't allow two instances to be created. The entire idea of dispatch_once() is "perform something once and only once", ...
pandas DataFrame: replace nan values with average of columns
... CAUTION: if you want to use this for Machine Learning / Data Science: from a Data Science perspective it is wrong to first replace NA and then split into train and test... You MUST first split into train and test, then replace NA by mean on train and then apply this stateful preprocessing model...
What's the magic of “-” (a dash) in command-line parameters?
...command, every time you change directory, it stores the directory you came from. If you do cd with the special - "directory name", it uses that remembered directory instead of a real one. You can easily switch between two directories quite quickly by using that.
Other commands may treat - as a diff...
What does the fpermissive flag do?
...
Right from the docs:
-fpermissive
Downgrade some diagnostics about nonconformant code from errors to warnings.
Thus, using -fpermissive will allow some nonconforming code to compile.
Bottom line: don't use it unl...