大约有 44,000 项符合查询结果（耗时：0.0473秒） [XML]
Can I run multiple versions of Google Chrome on the same machine? (Mac or Windows)
...fo.plist and change the value of <key>KSUpdateURL</key> to <string>https://tools.google.com/abcdefg</string>. No other method worked for me (including setting defaults write com.google.Keystone.Agent checkInterval 0).
– Abhishek Divekar
...
Declaring a custom android UI element using XML
...xtColor"/>
<attr name="extraInformation" format="string" />
</declare-styleable>
</resources>
Notice the use of an unqualified name in the declare-styleable tag. Non-standard android attributes like extraInformation need to have their type declared. Ta...
Securely storing environment variables in GAE with app.yaml
...m google.appengine.ext import ndb
class Settings(ndb.Model):
name = ndb.StringProperty()
value = ndb.StringProperty()
@staticmethod
def get(name):
NOT_SET_VALUE = "NOT SET"
retval = Settings.query(Settings.name == name).get()
if not retval:
retval = Settings()
retva...
How do I pass variables and data from PHP to JavaScript?
...beyond, limbo, the city of shimmers, and Canada.
*
* AJAX generally uses strings, but you can output JSON, HTML and XML as well.
* It all depends on the Content-type header that you send with your AJAX
* request. */
echo json_encode(42); // In the end, you need to echo the result.
...
How to ignore xargs commands if stdin input is empty?
... may take advantage of -L <#lines>, -n <#args>, -i, and -I <string>:
ls /empty_dir/ | xargs -n10 chown root # chown executed every 10 args or fewer
ls /empty_dir/ | xargs -L10 chown root # chown executed every 10 lines or fewer
ls /empty_dir/ | xargs -i cp {} {}.bak # every {} is ...
Determine Whether Two Date Ranges Overlap
...a syntactical shortcut for what is a longer implementation, which includes extra checks to verify that the start dates are on or before the endDates. Deriving this from above:
If start and end dates can be out of order, i.e., if it is possible that startA > endA or startB > endB, then you a...
Are loops really faster in reverse?
...
i-- is as fast as i++
This code below is as fast as yours, but uses an extra variable:
var up = Things.length;
for (var i = 0; i < up; i++) {
Things[i]
};
The recommendation is to NOT evaluate the size of the array each time. For big arrays one can see the performance degradation.
...
Centering a div block without the width
...S rule. This is a good trick to center a div in a container without adding extra HTML nor applying constraining styles to the container (like text-align: center; which would center all other inline content in the container), while keeping dynamic width for the contained div:
HTML:
<div class="c...
How do MySQL indexes work?
...lision number is high cause you'll only perform the second comparison (the string one) against the repeated hashes.
Unfortunately, using this technique, you still need to hit the table to compare the url field.
Wrap up
Some facts that you may consider every time you want to talk about optimizatio...
Virtual functions and performance - C++
...an instruction cache miss like a non-virtual function.
In many cases, two extra cache misses are not a concern, but in a tight loop on performance critical code it can dramatically reduce performance.
share
|
...