大约有 40,000 项符合查询结果（耗时：0.0740秒） [XML]
Difference between objectForKey and valueForKey?
...
I'm surprised no one has corrected this answer by pointing out valueForKey: technically does not give you access to the corresponding instance variable, but rather the accessor method that (could) manage the instance variable.
– Dany Joumaa
...
SQL “select where not in subquery” returns no results
...e efficient, since LEFT JOIN / IS NULL cannot be optimized to an ANTI JOIN by its optimizer.
In PostgreSQL, LEFT JOIN / IS NULL and NOT EXISTS are more efficient than NOT IN, sine they are optimized to an Anti Join, while NOT IN uses hashed subplan (or even a plain subplan if the subquery is too la...
ASP.NET: Session.SessionID changes between requests
...ay occur even when the Session object has been initialized as demonstrated by Cladudio.
In the Web.config, if there is an <httpCookies> entry that is set to requireSSL="true" but you are not actually using HTTPS: for a specific request, then the session cookie is not sent (or maybe not return...
difference between foldLeft and reduceLeft in Scala
...thus caused the confusion. reduceLeft is a special case of foldLeft (which by the way means that you sometimes can express the same thing by using either of them).
When you call reduceLeft say on a List[Int] it will literally reduce the whole list of integers into a single value, which is going to ...
sed edit file in place
... question was actually a very good one, but it's value has been diminished by people who either can't read man pages or can't be bothered to actually read questions here on SO.
– Steve
Oct 14 '14 at 1:28
...
What is ActiveMQ used for - can we apply messaging concept using a Database?
...ages to consumers instead of a consumer having to poll for the new message by doing a SQL query.
This further reduces the latency involved in processing new messages being sent into the system.
share
|
...
How to encode a URL in Swift [duplicate]
...ogleapis.com/maps/api/geocode/json?address=\(escapedAddress)")
Use stringByAddingPercentEncodingWithAllowedCharacters:
var escapedAddress = address.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())
Use stringByAddingPercentEscapesUsingEncoding: ...
Fragment onCreateView and onActivityCreated called twice
...mClass = clz;
mFragment=mActivity.getFragmentManager().findFragmentByTag(mTag);
}
public void onTabSelected(Tab tab, FragmentTransaction ft) {
if (mFragment == null) {
mFragment = Fragment.instantiate(mActivity, mClass.getName());
ft.replace(android.R...
Best approach to remove time part of datetime in SQL Server
...()), 0)
Proven less CPU intensive for same total duration a million rows by some one with way too much time on their hands: Most efficient way in SQL Server to get date from date+time?
I saw a similar test elsewhere with similar results too.
I prefer the DATEADD/DATEDIFF because:
varchar is su...
Merge PDF files
...ary built as a PDF toolkit. It is capable of:
* splitting documents page by page,
* merging documents page by page,
(and much more)
Here's a sample program that works with both versions.
#!/usr/bin/env python
import sys
try:
from PyPDF2 import PdfFileReader, PdfFileWriter
except Import...