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NSOperation vs Grand Central Dispatch
...ed first, but as of 10.5 and iOS 2, NSOperationQueue and friends are internally implemented using GCD.
In general, you should use the highest level of abstraction that suits your needs. This means that you should usually use NSOperationQueue instead of GCD, unless you need to do something that NSOp...
Google Chrome redirecting localhost to https
...t as per accepted answer, it does return 'not found'? Tried everything in all comments and answers here.
– DarkW1nter
May 10 '17 at 15:05
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Rounded table corners CSS only
... only, you get 2px thick borders, which is ugly. Rather have no borders at all.
– Vishal Shah
Feb 8 '11 at 11:27
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The tilde operator in C
...F hashing algorithm, and I'm curious what it does. (The code is from Eternally Confused .)
6 Answers
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What's the difference between passing by reference vs. passing by value?
...on as defined in the CS theory is now obsolete because the technique originally defined as "pass by reference" has since fallen out of favor and is seldom used now.1
Newer languages2 tend to use a different (but similar) pair of techniques to achieve the same effects (see below) which is the primar...
Learning Regular Expressions [closed]
I don't really understand regular expressions. Can you explain them to me in an easy-to-follow manner? If there are any online tools or books, could you also link to them?
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Comment shortcut Android Studio
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Mac With Numeric pad
Line Comment hold both: Cmd + /
Block Comment hold all three: Cmd + Alt + /
Mac
Line Comment hold both: Cmd + + =
Block Comment hold all three: Cmd + Alt + + =
Windows/linux :
Line Comment hold both: Ctrl + /
Block Comment hold all three: Ctrl + Shift + /
Same way to rem...
XPath: How to select nodes which have no attributes?
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//node[not(@*)]
That's the XPath to select all nodes named "node" in the document without any attributes.
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How to quietly remove a directory with content in PowerShell
...o remove everything within that folder: Remove-Item './folder/*'. If you really want to clear out only files of all folders you can list all leafs and pipe it to the Remove-Item cmdlet Get-ChildItem -Recurse -File | Remove-Item
– Michael Kargl
Jun 1 '19 at 11:3...
Replacing column values in a pandas DataFrame
...strings containing numbers. You can convert them to "1" and "0", if you really want, but I'm not sure why you'd want that.)
The reason your code doesn't work is because using ['female'] on a column (the second 'female' in your w['female']['female']) doesn't mean "select rows where the value is 'fe...