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Mean per group in a data.frame [duplicate]
... the many ways to specify the variables to act on. Here, vars(-Month) says all variables except Month.
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R: rJava package install failing
When installing rJava using the install.packages("rJava") command I get the following error:
16 Answers
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How to find out the MySQL root password
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Nice instruction flow especially: then run mysql in a new terminal
– Mohammed Subhi Sheikh Quroush
Mar 27 '15 at 7:49
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How does Stack Overflow generate its SEO-friendly URLs?
...I benchmarked it). I figured I'd optimize it because this function can be called hundreds of times per page.
/// <summary>
/// Produces optional, URL-friendly version of a title, "like-this-one".
/// hand-tuned for speed, reflects performance refactoring contributed
/// by John Gietzen (user...
How to copy from current position to the end of line in vi
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10
Add this line to your .vimrc
" Make Y yank till end of line
nnoremap Y y$
More at my vimrc....
Vibrate and Sound defaults on notification
...gb format, like 0xffffffff, instead of Color.White, because there's is a small chance of user device use Color(RGB) for a ARGB param and you will get the wrong color. This Happened with me.
– Beto Caldas
Oct 24 '14 at 19:47
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How to check if a file is a valid image file?
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That won't be sufficient if he's really testing for "valid" images; the presence of a magic number doesn't guarantee that the file hasn't been truncated, for example.
– Ben Blank
May 20 '09 at 18:11
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How to assign from a function which returns more than one value?
...eturningTwoValues()
If you only need the first or second component these all work too:
list[a] <- functionReturningTwoValues()
list[a, ] <- functionReturningTwoValues()
list[, b] <- functionReturningTwoValues()
(Of course, if you only needed one value then functionReturningTwoValues()[...
How can I get last characters of a string
...ng().slice(-5)
– dnns
Jul 19 '19 at 10:04
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How to check if a number is a power of 2
...nd only if both its operands are true.
Now let's take a look at how this all plays out:
The function returns boolean (true / false) and accepts one incoming parameter of type unsigned long (x, in this case). Let us for the sake of simplicity assume that someone has passed the value 4 and called ...