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What are the most interesting equivalences arising from the Curry-Howard Isomorphism?
...pon the Curry-Howard Isomorphism relatively late in my programming life, and perhaps this contributes to my being utterly fascinated by it. It implies that for every programming concept there exists a precise analogue in formal logic, and vice versa. Here's a "basic" list of such analogies, off th...
How to check if a line is blank using regex
...e character class.
* is zero-or-more repetition of.
In multiline mode, ^ and $ also match the beginning and end of the line.
References:
regular-expressions.info/Anchors, Character Classes, and Repetition.
A non-regex alternative:
You can also check if a given string line is "blank" (i.e. ...
Add one row to pandas DataFrame
I understand that pandas is designed to load fully populated DataFrame but I need to create an empty DataFrame then add rows, one by one .
What is the best way to do this ?
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About Android image and asset sizes
...imply using hdpi assets.
What this means is if you're doing a 48dip image and plan to support up to xxhdpi resolution, you should start with a 144px image (192px if you want native assets for xxxhdpi) and make the following images for the densities:
ldpi | mdpi | tvdpi | hdpi | xhdpi ...
How is the java memory pool divided?
... data area from which the Java VM allocates memory for all class instances and arrays. The heap may be of a fixed or variable size. The garbage collector is an automatic memory management system that reclaims heap memory for objects.
Eden Space: The pool from which memory is initially allocated fo...
How to grep (search) committed code in the Git history
...ommit content (i.e., actual lines of source, as opposed to commit messages and the like), you need to do:
git grep <regexp> $(git rev-list --all)
git rev-list --all | xargs git grep <expression> will work if you run into an "Argument list too long" error.
If you want to limit the sea...
How to use JavaScript source maps (.map files)?
...js.map extension shipped with some JavaScript libraries (like Angular ), and that just raised few questions in my head:
5...
Ruby on Rails Callback, what is difference between :before_save and :before_create?
Could you explain in detail what the :before_save and :before_create Ruby on Rails callbacks are, and what they have to do with Rails validations? Does validation occur after :before_save or :before_create ?
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Difference between os.getenv and os.environ.get
...s about os.environ.get() which returns None (unless specified differently) and never raises an exception if the env. var. doesn't exists. Your confusing things with using os.environ['TERM'] which is not what the question is about.
– Anthon
Apr 21 '17 at 7:41
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What does -fPIC mean when building a shared library?
I know the ' -fPIC ' option has something to do with resolving addresses and independence between individual modules, but I'm not sure what it really means. Can you explain?
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