大约有 43,000 项符合查询结果(耗时:0.0409秒) [XML]
What can I do with a moved-from object?
...should be a separate question, but does that mean: if I have a string with char* buffer; and int length; members, then my move constructor/assignment must swap (or set) the value of both? Or would it be OK, if the length was unspecified (meaning that empty and size return meaningless values)?
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Is there any performance gain in indexing a boolean field?
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It depends on the actual queries and the selectivity of the index/query combination.
Case A: condition WHERE isok = 1 and nothing else there:
SELECT *
FROM tableX
WHERE isok = 1
If the index is selective enough (say you have 1M rows and only 1k have isok = 1), ...
How can I selectively escape percent (%) in Python strings?
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>>> test = "have it break."
>>> selectiveEscape = "Print percent %% in sentence and not %s" % test
>>> print selectiveEscape
Print percent % in sentence and not have it break.
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iOS app with framework crashed on device, dyld: Library not loaded, Xcode 6 Beta
...r Products folder in your project.
Right click on your .framework and select "Show in Finder".
3) Place framework in your project
Drag and drop the .framework from your Finder window to your app project's "Framework" folder.
4) Configure app project for framework
Select the top leve...
Querying data by joining two tables in two database on different servers
...just prefixing the database name with the other server. I.E:
-- FROM DB1
SELECT *
FROM [MyDatabaseOnDB1].[dbo].[MyTable] tab1
INNER JOIN [DB2].[MyDatabaseOnDB2].[dbo].[MyOtherTable] tab2
ON tab1.ID = tab2.ID
Once the link is established, you can also use OPENQUERY to execute a SQL st...
Replace new lines with a comma delimiter with Notepad++?
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Open the find and replace dialog (press CTRL+H).
Then select Regular expression in the 'Search Mode' section at the bottom.
In the Find what field enter this: [\r\n]+
In the Replace with: ,
There is a space after the comma.
This will also replace lines like
Apples
Apri...
Entity Framework and SQL Server View
...mn as a primary key, use NULLIF.
An easy way to apply this is to wrap the select statement of your view in another select.
Example:
SELECT
ISNULL(MyPrimaryID,-999) MyPrimaryID,
NULLIF(AnotherProperty,'') AnotherProperty
FROM ( ... ) AS temp
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JSON encode MySQL results
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$sth = mysqli_query($conn, "SELECT ...");
$rows = array();
while($r = mysqli_fetch_assoc($sth)) {
$rows[] = $r;
}
print json_encode($rows);
The function json_encode needs PHP >= 5.2 and the php-json package - as mentioned here
NOTE: mysql is dep...
How to check if an element does NOT have a specific class?
...t one for the case in the question, but just as a reference if you need to select elements that don't have a certain class, you can use the not selector:
// select all divs that don't have class test
$( 'div' ).not( ".test" );
$( 'div:not(.test)' ); // <-- alternative
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HTML File Selection Event
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I think @anthony is referring to the following scenario: Select a file. Now open the file selector again, but this time click on Cancel. Since no file was selected the second time, the file input control resets, thus changing its initial selection, and the change event is fired.
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