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Why do we need extern “C”{ #include } in C++?
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C and C++ are superficially similar, but each compiles into a very different set of code. When you include a header file with a C++ compiler, the compiler is expecting C++ code. If, however, it is a C header, then the compiler expects the data contained i...
Is there a good reason I see VARCHAR(255) used so often (as opposed to another length)?
In multiple courses, books, and jobs, I have seen text fields defined as VARCHAR(255) as kind of the default for "shortish" text. Is there any good reason that a length of 255 is chosen so often, other than being a nice round number ? Is it a holdout from some time in the past when there was a go...
How can I add a key/value pair to a JavaScript object?
Here is my object literal:
24 Answers
24
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Function to calculate distance between two coordinates
I'm currently using the function below and it doesn't work properly. According to Google Maps, the distance between these coordinates (from 59.3293371,13.4877472 to 59.3225525,13.4619422 ) are 2.2 kilometres while the function returns 1.6 kilometres. How can I make this function return the ...
What happens when there's insufficient memory to throw an OutOfMemoryError?
I am aware that every object requires heap memory and every primitive/reference on the stack requires stack memory.
11 Answ...
How can I get a side-by-side diff when I do “git diff”?
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Although Git has an internal implementation of diff, you can set up an external tool instead.
There are two different ways to specify an external diff tool:
setting the GIT_EXTERNAL_DIFF and the GIT_DIFF_OPTS environment variables.
configuring the ext...
Hidden features of Scala
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Okay, I had to add one more. Every Regex object in Scala has an extractor (see answer from oxbox_lakes above) that gives you access to the match groups. So you can do something like:
// Regex to split a date in the format Y/M/D.
val regex = "(\\...
Why doesn't Java support unsigned ints?
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This is from an interview with Gosling and others, about simplicity:
Gosling: For me as a language designer, which I don't really count myself as these days, what "simple" really ended up meaning was could I expect J. Random Develop...
How to delete a row by reference in data.table?
My question is related to assignment by reference versus copying in data.table . I want to know if one can delete rows by reference, similar to
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How to write DataFrame to postgres table?
There is DataFrame.to_sql method, but it works only for mysql, sqlite and oracle databases. I cant pass to this method postgres connection or sqlalchemy engine.
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