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What are the effects of exceptions on performance in Java?
... the exceptions themselves, the exact actions taken in exception handlers, etc.
The upshot is that when an exception isn't thrown, you don't pay a cost, so when the exceptional condition is sufficiently rare exception handling is faster than using an if every time. The full post is very much worth...
Referring to the null object in Python
...nd is used to control and test special conditions (e.g. boundaries, state, etc.). Such a value is called a sentinel and it can be used the way None is used as a signal. It's trivial to create a sentinel in Python.
undefined = object()
The undefined object above is unique and doesn't do much of anyt...
Understanding the Use of ColorMatrix and ColorMatrixColorFilter to Modify a Drawable's Hue
...Note that a lot more can be done with color matrices. Including inverting, etc...
public class ColorFilterGenerator
{
/**
* Creates a HUE ajustment ColorFilter
* @see http://groups.google.com/group/android-developers/browse_thread/thread/9e215c83c3819953
* @see http://gskinner.com/blog/archi...
What is the purpose of setting a key in data.table?
...along with associated information (city, state, population, median income, etc.). If I want to look up the information for a specific zip code, the search (filter) is about 1000 times faster if I setkey(ZIP,zipcode) first.
Another benefit has to do with joins. Suppose a have a list of people and th...
What's the difference between “groups” and “captures” in .NET regular expressions?
...avior causes group's specification, like (...)(...), (...){2} or (.{3}){2} etc.
Hopefully it will help shed some light on the differences between Captures, Groups and Matches as well.
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imp...
Shell脚本编程30分钟入门 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...接赋值，还可以用语句给变量赋值，如：
for file in `ls /etc`
使用变量
使用一个定义过的变量，只要在变量名前面加美元符号即可，如：
your_name="qinjx"
echo $your_name
echo ${your_name}
变量名外面的花括号是可选的，加不加都行...
Tactics for using PHP in a high-load site
...l of the file concatenations, minification, file renaming to include hash, etc for all static content. It'll should only add a little processing overhead to the servers initially until the caches (and CDN(s)) are populated with most of the content. Also, for security, it's generally a bad idea to pu...
What does the Java assert keyword do, and when should it be used?
... try to trap, log, or retry/recover from OutOfMemoryError, AssertionError, etc.
– Aleksandr Dubinsky
Jun 16 '16 at 21:39
1
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is there a css hack for safari only NOT chrome?
... by posting a comment about it, Post Your Browser and Device (MacBook/IPad/etc... with both browser and OS version numbers!)
Claiming none of these work is not accurate (and actually not even possible.) Many of these are not really 'hacks' but code built into versions of Safari by Apple. More info i...
How to handle Handler messages when activity/fragment is paused
...savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
if (savedInstanceState == null) {
final Fragment state = new State();
final FragmentManager fm = getFragmentManager();
final FragmentTransaction ft = ...