大约有 47,000 项符合查询结果（耗时：0.0579秒） [XML]
Tricks to manage the available memory in an R session
...
I make aggressive use of the subset parameter with selection of only the required variables when passing dataframes to the data= argument of regression functions. It does result in some errors if I forget to add variables to both the formula and the select= vector, but it sti...
Can't find a “not equal” css attribute selector
...
One problem with the accepted answer is that it will also select elements that do not have a foo attribute at all. Consider:
<div>No foo</div>
<div foo="">Empty foo</div>
<div foo="x">XXX</div>
<div foo="y">YYY</div>
<div foo="z"&g...
Does async(launch::async) in C++11 make thread pools obsolete for avoiding expensive thread creation
...rong. I was under the impression that Linux thread creation was very cheap and after testing I determined that the overhead of function call in a new thread vs. a normal one is enormous. The overhead for creating a thread to handle a function call is something like 10000 or more times slower than a ...
Undoing a commit in TortoiseSVN
...
Go to Show Log Screen, select the revision that you want to undo, right click it and select Revert changes from this revision, this will do a reverse-merge.
share
...
How does a PreparedStatement avoid or prevent SQL injection?
...o in detail.
Compilation Phase:
In this phase, keywords used in query like select, from, where etc are converted into format
understandable by machine.
This is the phase where query is interpreted and corresponding action to be taken is decided.
It also has many other tasks to do, but let's not go ...
Applying a git post-commit hook to all current and future repos
I've written a Git post-commit hook and it works correctly. However, I want to add this hook to apply to all current (and future) git repositories I am working on. I tried adding the hook to my ~/.git/hooks/ instead of in the hooks directory in the project directory, however, this did not seem t...
Visual Studio: Make view code default
...
Right-click on a file and select "Open With..."
Select "CSharp Editor" and then click "Set as Default".
share
|
improve this answer
|
...
What's the $unwind operator in MongoDB?
...oDB employs an "NoSQL" approach to data storage, so perish the thoughts of selects, joins, etc. from your mind. The way that it stores your data is in the form of documents and collections, which allows for a dynamic means of adding and obtaining the data from your storage locations.
That being sai...
Is the creation of Java class files deterministic?
...Oracle's javac actually produce different class files for the same input and compiler options?
11 Answers
...
How to change the CHARACTER SET (and COLLATION) throughout a database?
...re schema to utf8. Hope this helps!
-- Change DATABASE Default Collation
SELECT DISTINCT concat('ALTER DATABASE `', TABLE_SCHEMA, '` CHARACTER SET utf8 COLLATE utf8_unicode_ci;')
from information_schema.tables
where TABLE_SCHEMA like 'database_name';
-- Change TABLE Collation / Char Set
SELECT...