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Drop unused factor levels in a subsetted data frame

...tion, a new data frame is created. However, the factor variable retains all of its original levels, even when/if they do not exist in the new dataframe. ...
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How to set timeout on python's socket recv method?

...lect() to wait until data is available or until the timeout occurs. Only call recv() when data is actually available. To be safe, we also set the socket to non-blocking mode to guarantee that recv() will never block indefinitely. select() can also be used to wait on more than one socket at a time...
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Xcode Command /usr/bin/codesign failed with exit code 1 : errSecInternalComponent

... Open Keychain Access, then in the File menu select Lock All Keychains. Then go back to Xcode and clean and rebuild. It will prompt you for your password again to unlock the keychain. After this, assuming you have no other compile issues, it will succeed! ...
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How to run Visual Studio post-build events for debug build only

...figuration)" == "Debug" worked for me. BTW, if you want to do something in all other configs, use if NOT "$(Configuration)" == "Debug". – Ralf Hundewadt Jun 29 '17 at 9:46 ...
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Read String line by line

...s = myString.split(System.getProperty("line.separator")); This gives you all lines in a handy array. I don't know about the performance of split. It uses regular expressions. share | improve thi...
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Flexbox Not Centering Vertically in IE

... I found that ie browser have problem to vertically align inner containers, when only the min-height style is set or when height style is missing at all. What I did was to add height style with some value and that fix the issue for me. for example : .outer { ...
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UnicodeDecodeError: 'charmap' codec can't decode byte X in position Y: character maps to

...re out yourself. Common ones are Latin-1 and UTF-8. Since 0x90 doesn't actually mean anything in Latin-1, UTF-8 (where 0x90 is a continuation byte) is more likely. You specify the encoding when you open the file: file = open(filename, encoding="utf8") ...
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Haskell offline documentation?

... Hoogle is available offline, installable from Cabal: http://hackage.haskell.org/package/hoogle Usage instructions are at http://www.haskell.org/haskellwiki/Hoogle#Command_Line_Search_Flags. Usage: $ hoogle --help Hoogle v4.2.8, (C) Neil Mitchell 2004-2011...
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Where could I buy a valid SSL certificate? [closed]

...d" message. I realized that you need an intermediate certificate. When installing a startssl cert make sure you follow the steps here: startssl.com/?app=20 (for me I selected nginx) make sure you follow the part about the intermediate cert. Also you can double check cert problems here: sslshopper.co...
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jQuery: how to get which button was clicked upon form submission?

... Oh, I see. You're adding your own "clicked" attribute. I was looking all over for a "clicked" boolean and couldn't find one anywhere. I never thought of making one myself. Good idea! – hawkexp Apr 19 '11 at 20:33 ...