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How does type Dynamic work and how to use it?
...cs
or set the compiler option -language:dynamics because the feature is hidden by default.
selectDynamic
selectDynamic is the easiest one to implement. The compiler translates a call of foo.bar to foo.selectDynamic("bar"), thus it is required that this method has an argument list expecting a Str...
Very simple log4j2 XML configuration file using Console and File appender
...)
Use Logger logger = LogManager.getLogger(); to initialize your logger
I did set the immediateFlush="false" since this is better for SSD lifetime. If you need the log right away in your log-file remove the parameter or set it to true
...
Equation (expression) parser with precedence?
... code like say, Aperture with GCC and they sell it without having to GPL said code).
Download Bison (or something equivalent, ANTLR, etc.).
There is usually some sample code that you can just run bison on and get your desired C code that demonstrates this four function calculator:
http://www.gnu....
How Python web frameworks, WSGI and CGI fit together
...POST-oriented input as a file-like object in the environment. It also provides you a function that will formulate the response, saving you from a lot of formatting details.
What do I need to know / install / do if I want to run a web framework (say web.py or cherrypy) on my basic CGI configuration...
Understanding exactly when a data.table is a reference to (vs a copy of) another data.table
...just changing the elements that need to be changed. That's important to avoid for large data, and why := and set() were introduced to data.table.
Now, with our copied newDT we can modify it by reference :
newDT
# a b
# [1,] 1 11
# [2,] 2 200
newDT[2, b := 400]
# a b # See FA...
What MIME type should I use for CSV?
...arameters: None
Optional parameters: name
Encoding considerations: base64 preferred
Security considerations: As with most application types this data is
intended for interpretation by a program that understands the data on
the recipient's system. Recipients need to und...
Git pull results in extraneous “Merge branch” messages in commit log
... to use rebasing instead of merging is possible, but usually you should avoid it. Rebasing allows you to keep a linear history, but also removes any information about the branching that originally happened. It will also cause the history of the current branch being rewritten, recreating all commits ...
What does “abstract over” mean?
...this really means we're integrating by the similarities.
For example, consider a program that takes the sum of the numbers 1, 2, and 3:
val sumOfOneTwoThree = 1 + 2 + 3
This program is not very interesting, since it's not very abstract. We can abstract over the numbers we're summing, by integrat...
What is the fastest integer division supporting division by zero no matter what the result is?
...
Inspired by some of the comments I got rid of the branch on my Pentium and gcc compiler using
int f (int x, int y)
{
y += y == 0;
return x/y;
}
The compiler basically recognizes that it can use a condition flag of the test in the addition.
As pe...
How do you validate a URL with a regular expression in Python?
...
An easy way to parse (and validate) URL's is the urlparse (py2, py3) module.
A regex is too much work.
There's no "validate" method because almost anything is a valid URL. There are some punctuation rules for splitting it up. Absent any punctuati...