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What is a regular expression which will match a valid domain name without a subdomain?
...ote, to use this regex, you will need to convert the domain to lower case, and also use an IDN library to ensure you encode domain names to ACE (also known as "ASCII Compatible Encoding"). One good library is GNU-Libidn.
idn(1) is the command line interface to the internationalized domain name libr...
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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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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How to check if one of the following items is in a list?
... S2 = set(L2)
>>> S1.intersection(S2)
set([2])
Both empty lists and empty sets are False, so you can use the value directly as a truth value.
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How do I add the contents of an iterable to a set?
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Just looked back at my interpreter session and I actually tried this, but thought that it had added the whole list as an element of the set because of the square brackets in the representation of the set. I had never noticed before that they're represented like that.
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Import regular CSS file in SCSS file?
Is there anyway to import a regular CSS file with Sass's @import command? While I'm not using all of the SCSS syntax from sass, I do still enjoy it's combining/compressing features, and would like to be able to use it without renaming all of my files to *.scss
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Why is it OK to return a 'vector' from a function?
...a copy of the return value actually (available at least with the current standard).
– πάντα ῥεῖ
Feb 9 '15 at 20:46
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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...
Using semicolon (;) vs plus (+) with exec in find
...+), as many filenames as possible are passed as arguments to a single command:
ls file1 file2 file3
The number of filenames is only limited by the system's maximum command line length. If the command exceeds this length, the command will be called multiple times.
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How to install Boost on Ubuntu
I'm on Ubuntu, and I want to install Boost. I tried with
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