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Summarizing multiple columns with dplyr? [duplicate]
...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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Using do block vs braces {}
...Agreed, although I prefer to assign the result of a method with block to a meaningful variable and then call another method on it like result_with_some_condition = method{|c| c.do_something || whateever}; result_with_some_condition.another_method as that just makes it a bit more easily understandabl...
What is the difference between ${var}, “$var”, and “${var}” in the Bash shell?
What the title says: what does it mean to encapsulate a variable in {} , "" , or "{} "? I haven't been able to find any explanations online about this - I haven't been able to refer to them except for using the symbols, which doesn't yield anything.
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Why number 9 in kill -9 command in unix? [closed]
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Back in the day (by which I mean 4.xBSD or so) you couldn't use the mnemonics with the shell command, which is why the number 9 is written into an awful lot of old dusty-deck shell scripts.
– zwol
Mar 30 '12 at 23:...
Are there pronounceable names for common Haskell operators? [closed]
...amples --
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-- "(:) <$> Just 3 <*> Just [4]"
-- meaning "Cons applied to just three applied to just list with one element four"
t "(:)" = "Cons"
t "Just" = "just"
t "<$>" = "applied to"
t "3" = "three" -- this is might go a bit too far
t "[4]" = "list with one ...
How to prevent a dialog from closing when a button is clicked
...e your code that calls show() will be operating on the main GUI thread, it means whatever code you follow show() with will be executed before any other code on that thread, whereas the timing of the OnShowListener method is at the mercy of the message queue.
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What does send() do in Ruby?
...ful for unit testing).
If there is really no variable before send, that means that the global Object is used:
send :to_s # "main"
send :class # Object
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Testing if object is of generic type in C#
...his checks the exact type equivalence. Returning false doesn't necessarily mean list is List<T> returns false (i.e. the object cannot be assigned to a List<T> variable).
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Why should Java ThreadLocal variables be static
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@optional It just means each instance of the non-static ThreadLocal would hold it's own thread-local data even if those ThreadLocal instances exist in the same thread. It isn't necessarily wrong to do that -- I suppose it just might be the lea...
'parent.relativePath' points at my com.mycompany:MyProject instead of org.apache:apache - Why?
... suspect this default behavior is causing some other problems. What do you mean by 'enter the element'?
– simpatico
May 14 '11 at 20:09
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