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Summarizing multiple columns with dplyr? [duplicate]
... a bit with the dplyr-syntax. I have a data frame with different variables and one grouping variable. Now I want to calculate the mean for each column within each group, using dplyr in R.
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Interface or an Abstract Class: which one to use?
Please explain when I should use a PHP interface and when I should use an abstract class ?
11 Answers
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How does this print “hello world”?
...th this codification scheme you can have all 26 (one case) english letters and 6 symbols (being space among them).
Algorithm description
The >>= 5 in the for-loop jumps from group to group, then the 5-bits group gets isolated ANDing the number with the mask 31₁₀ = 11111₂ in the sentenc...
Programmatically create a UIView with color gradient
...gColor]
view.layer.insertSublayer(gradient, at: 0)
Info: use startPoint and endPoint to change direction of gradient.
If there are any other views added onto this UIView (such as a UILabel), you may want to consider setting the background color of those UIView’s to [UIColor clearColor] so the ...
What is the correct SQL type to store a .Net Timespan with values > 24:00:00?
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I'd store it in the database as a BIGINT and I'd store the number of ticks (eg. TimeSpan.Ticks property).
That way, if I wanted to get a TimeSpan object when I retrieve it, I could just do TimeSpan.FromTicks(value) which would be easy.
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What is the correct syntax for 'else if'?
... python "else if" is spelled "elif".
Also, you need a colon after the elif and the else.
Simple answer to a simple question. I had the same problem, when I first started (in the last couple of weeks).
So your code should read:
def function(a):
if a == '1':
print('1a')
elif a == '2...
Make .git directory web inaccessible
I have a website that I use github (closed source) to track changes and update site. The only problem is, it appears the .git directory is accessible via the web. How can I stop this and still be able to use git?
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Visual Studio build fails: unable to copy exe-file from obj\debug to bin\debug
...ducing this bug can be found here at Microsoft Connect. I have also tested and verified that the solution given in the accepted answer below works on that sample project. If this solution doesn't work for you, you are probably having a different issue (which belongs in a separate question).
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iOS5 Storyboard error: Storyboards are unavailable on iOS 4.3 and prior
I've built a small app using storyboards and it ran great. Just before final testing I decided to try it out to see if it runs on iOS 4.3. I clicked on the gray 5.0 in the project settings and selected 4.3.
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Table Naming Dilemma: Singular vs. Plural Names [closed]
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Others have given pretty good answers as far as "standards" go, but I just wanted to add this... Is it possible that "User" (or "Users") is not actually a full description of the data held in the table? Not that you should get too crazy with table names and specificity, but p...