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Regular Expression for alphanumeric and underscores
...e to have a regular expression that checks if a string contains only upper and lowercase letters, numbers, and underscores.
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Best explanation for languages without null
...deling a door. It can be in one of three states: open, shut but unlocked, and shut and locked. Now I could model it along the lines of
class Door
private bool isShut
private bool isLocked
and it is clear how to map my three states into these two boolean variables. But this leaves a fou...
Guards vs. if-then-else vs. cases in Haskell
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From a technical standpoint, all three versions are equivalent.
That being said, my rule of thumb for styles is that if you can read it as if it was English (read | as "when", | otherwise as "otherwise" and = as "is" or "be"), you're probably ...
moving changed files to another branch for check-in
This often happens to me: I write some code, go to check in my changes, and then realize I'm not in the proper branch to check in those changes. However I can't switch to another branch without my changes reverting. Is there a way to move changes to another branch to be checked in there?
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How to make div background color transparent in CSS
...that allows you to do that.
Just create a new image, delete the background and put a semi-transparent color in it, then save it in png.)
As said by René, the best thing to do would be to mix both, with the rgba first and the 1px by 1px image as a fallback if the browser doesn't support alpha :
ba...
MySQL stored procedure vs function, which would I use when?
I'm looking at MySQL stored procedures and function. What is the real difference?
5 Answers
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how to find host name from IP with out login to the host
...s. When this option is used, there is no
need to provide the name, class and type arguments. dig automatically
performs a lookup for a name like 11.12.13.10.in-addr.arpa and sets
the query type and class to PTR and IN respectively.
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How is this fibonacci-function memoized?
...mechanism in Haskell is by-need: when a value is needed, it is calculated, and kept ready in case it is asked for again. If we define some list, xs=[0..] and later ask for its 100th element, xs!!99, the 100th slot in the list gets "fleshed out", holding the number 99 now, ready for next access.
Th...
What is the “assert” function?
I've been studying OpenCV tutorials and came across the assert function; what does it do?
9 Answers
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CSS :after not adding content to certain elements
I'm having trouble understanding the behavior of the CSS :after property. According to the spec ( here and here ):
3 An...