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Why switch is faster than if
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Because there are special bytecodes that allow efficient switch statement evaluation when there are a lot of cases.
If implemented with IF-statements you would have a check, a jump to the next clause, a check, a jump to the next clause and so on. With switch the JV...
Python: try statement in a single line
...ther dynamic languages. The safer way (and the prevailing style) is to set all variables to something. If they might not get set, set them to None first (or 0 or '' or something if it is more applicable.)
If you do assign all the names you are interested in first, you do have options.
The best...
How to use Git Revert
...nges to a file will often reach for revert before being told that they actually want reset.
Similarly, the revert equivalent in other VCSes is often called rollback or something similar - but "rollback" can also mean "I want to completely discard the last few commits", which is appropriate for rese...
What are copy elision and return value optimization?
... is an optimization implemented by most compilers to prevent extra (potentially expensive) copies in certain situations. It makes returning by value or pass-by-value feasible in practice (restrictions apply).
It's the only form of optimization that elides (ha!) the as-if rule - copy elision can be a...
Behaviour of increment and decrement operators in Python
...e applied on a variable (like ++count ). It compiles, but it does not actually change the value of the variable!
9 Answers...
Easiest way to pass an AngularJS scope variable from directive to controller?
...est way to pass an AngularJS scope variable from directive to controller? All of the examples that I've seen seem so complex, isn't there a way I can access a controller from a directive, and set one of it's scope variables?
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Python os.path.join on Windows
...'c:' 'c:\\' did not work (C:\\ created two backslashes, C:\ didn't work at all) Thanks again ghostdog74, Smashery, and Roger Pate. I am in your debt :)
– Frank E.
Mar 11 '10 at 6:12
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Is there a short contains function for lists?
...her have said, you may also be interested to know that what in does is to call the list.__contains__ method, that you can define on any class you write and can get extremely handy to use python at his full extent.
A dumb use may be:
>>> class ContainsEverything:
def __init__(self):...
Delete files older than 15 days using PowerShell
...is in the title of this post), but here's some code that will first delete all of the files older than 15 days, and then recursively delete any empty directories that may have been left behind. My code also uses the -Force option to delete hidden and read-only files as well. Also, I chose to not use...
Efficiency of purely functional programming
...ssible asymptotic slowdown that can happen when programming purely functionally as opposed to imperatively (i.e. allowing side-effects)?
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