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Drop unused factor levels in a subsetted data frame
...if(is.factor(x)) factor(x) else x) ...Is drop.levels() much more efficient computationally or better with large data sets? (One would have to rewrite the line above in a for-loop for a huge data frame, I suppose.)
– hatmatrix
Jul 29 '09 at 17:09
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Xcode 6 iPhone Simulator Application Support location
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The xcrun simctl list command can be used to see the correspondence between the simulator names and the device UDIDs. Or more specifically the xcrun simctl list devices command.
– ThomasW
Oct 2 '14 at 10:28
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CSS background image to fit width, height should auto-scale in proportion
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There is a CSS3 property for this, namely background-size (compatibility check). While one can set length values, it's usually used with the special values contain and cover. In your specific case, you should use cover:
body {
background-image: url(images/background.svg);
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Gmail Error :The SMTP server requires a secure connection or the client was not authenticated. The s
...enerally happens when you try login from different time zone or IP Address Computer. Your production server and the mail id you have used both are in different time zone. Choose either of these two solutions:
1) Log in to production server via remote access, and sign in to gmail once with your cred...
Visual Studio debugging “quick watch” tool and lambda expressions
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Lambda expressions, like anonymous methods, are actually very complex beasts. Even if we rule out Expression (.NET 3.5), that still leaves a lot of complexity, not least being captured variables, which fundamentally re-structure the code that uses them (what you think of as variables be...
Is there a stopwatch in Java?
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Use Guava's Stopwatch class.
An object that measures elapsed time in nanoseconds. It is use...
How to set environment variables in Jenkins?
...t "Properties File Path" to propsfile.
Note: This plugin is (mostly) not compatible with the Pipeline plugin.
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What exactly does the .join() method do?
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join takes an iterable thing as an argument. Usually it's a list. The problem in your case is...
Is there a Python Library that contains a list of all the ascii characters?
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Database design for a survey [closed]
...survey contains different types of questions. For example: text fields for comments, multiple choice questions, and possibly questions that could contain more than one answer (i.e. check all that apply).
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