大约有 45,000 项符合查询结果（耗时：0.0572秒） [XML]
Assign multiple columns using := in data.table, by group
...
This now works in v1.8.3 on R-Forge. Thanks for highlighting it!
x <- data.table(a = 1:3, b = 1:6)
f <- function(x) {list("hi", "hello")}
x[ , c("col1", "col2") := f(), by = a][]
# a b col1 col2
# 1: 1 1 hi hello
# ...
Function passed as template argument
...cout << "Result is " << temp << std::endl;
}
which can now be called as either:
doOperation(add2);
doOperation(add3());
See it live
The problem with this is that if it makes it tricky for the compiler to inline the call to add2, since all the compiler knows is that a function...
Remove/Add Line Breaks after Specific String using Sublime Text
...
Seems so obvious now... thanks a million! Also, @Mauro - I'm on Windows, and I can used ctrl + d to select the next iteration of the selection. Perhaps the same functionality exists on MAC with Command + d ? You may have to press it numerous ...
CSS for grabbing cursors (drag & drop)
... I saw the move icon, thought the grab icon was better. But now that you pointed out w3c considers that cursor "Indicates something is to be moved," it makes the most sense. Thanks.
– at.
Apr 18 '11 at 7:05
...
brew update: The following untracked working tree files would be overwritten by merge:
...ntually run brew doctor again to ensure yourself that the warning is gone.
Now, you should have a
Warning: You have uncommitted modifications to Homebrew
that may bey solved by
cd /usr/local/Library && git stash && git clean -d -f
as suggested by Dr.Brew itself. The command sta...
mysql - how many columns is too many?
I'm setting up a table that might have upwards of 70 columns. I'm now thinking about splitting it up as some of the data in the columns won't be needed every time the table is accessed. Then again, if I do this I'm left with having to use joins.
...
Visual Studio keyboard shortcut to automatically add the needed 'using' statement
...
Wow, didn't know about Ctrl+. or Alt+Shift+F10, but always wondered if there was such a short-cut. I also have a function lock keyboard, but it always remembers its state, so no problem here (Microsoft Natural Ergonomics Keyboard 4000).
...
Execute and get the output of a shell command in node.js
...
Thats the way I do it in a project I am working now.
var exec = require('child_process').exec;
function execute(command, callback){
exec(command, function(error, stdout, stderr){ callback(stdout); });
};
Example: Retrieving git user
module.exports.getGitUser = func...
What is the purpose of the “Prefer 32-bit” setting in Visual Studio and how does it actually work?
...T projects is again AnyCPU, but there is more than
one meaning to AnyCPU now. There is an additional sub-type of AnyCPU,
“Any CPU 32-bit preferred”, which is the new default (overall, there
are now five options for the /platform C# compiler switch: x86,
Itanium, x64, anycpu, and anycpu32...
const char * const versus const char *?
...
(I know this is old but I wanted to share anyway.)
Just wanted to elaborate on Thomas Matthews' answer. The Right-Left Rule of C type declarations pretty much says: when reading a C type declaration start at the identifier and g...