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What is the purpose of Rank2Types?
... arguments?
They do, but only of rank 1. This means that while you can write a function that takes different types of arguments without this extension, you can't write a function that uses its argument as different types in the same invocation.
For example the following function can't be typed wi...
How to list all users in a Linux group?
... pam-pgsql, etc.).
If I absolutely had to do this myself, I'd probably do it in reverse: use id to get the groups of every user on the system (which will pull all sources visible to NSS), and use Perl or something similar to maintain a hash table for each group discovered noting the membership of t...
MySQL OPTIMIZE all tables?
...ents for much more in depth thought on this topic than I can provide in limited space here: xaprb.com/blog/2010/02/07/…
– Ike Walker
Oct 23 '12 at 21:19
18
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Drop data frame columns by name
...to keep and refer to them by name :
keeps <- c("y", "a")
DF[keeps]
EDIT :
For those still not acquainted with the drop argument of the indexing function, if you want to keep one column as a data frame, you do:
keeps <- "y"
DF[ , keeps, drop = FALSE]
drop=TRUE (or not mentioning it) will ...
Download File to server from URL
Well, this one seems quite simple, and it is. All you have to do to download a file to your server is:
10 Answers
...
Why does Vim save files with a ~ extension?
...
The *.ext~ file is a backup file, containing the file as it was before you edited it.
The *.ext.swp file is the swap file, which serves as a lock file and contains the undo/redo history as well as any other internal info Vim needs. In case of a crash you can re-open your file and ...
Why do we need the “finally” clause in Python?
...
It makes a difference if you return early:
try:
run_code1()
except TypeError:
run_code2()
return None # The finally block is run before the method returns
finally:
other_code()
Compare to this:
try:
...
Is it possible to change only the alpha of a rgba background colour on hover?
I have a set of <a> tags with differing rgba background colours but the same alpha. Is it possible to write a single css style that will change only the opacity of the rgba attribute?
...
No 'Access-Control-Allow-Origin' - Node / Apache Port Issue
...venience):
// Add headers
app.use(function (req, res, next) {
// Website you wish to allow to connect
res.setHeader('Access-Control-Allow-Origin', 'http://localhost:8888');
// Request methods you wish to allow
res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT,...
CGridCellNumeric - A numeric cell class for the MFC Grid - C/C++ - 清...
...ridCGridCellNumeric-A-numeric-cell-class-for-the-MFC-GridA locale aware, editable, self validating numeric cell class for the MFC Grid. Configurable for integers, floating...A locale aware, editable, self validating numeric cell class for the MFC Grid. Configurable for integers, floating point, or c...