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How can i tell if an object has a key value observer attached
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Put a try catch around your removeObserver call
@try{
[someObject removeObserver:someObserver forKeyPath:somePath];
}@catch(id anException){
//do nothing, obviously it wasn't attached because an exception was thrown
}
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How do I count the number of occurrences of a char in a String?
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The loop method is much faster than this. Especially when wanting to count a char instead of a String (since there is no String.replace(char, char) method). On a 15 character string, I get a difference of 6049 ns vs 26,739 ns (averaged over 100runs). Raw numbers are huge...
setuptools: package data folder location
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alexsmail
5,26377 gold badges3232 silver badges5252 bronze badges
answered Oct 23 '14 at 17:31
polvoazulpolvoazul
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Python Linked List
...le to reference separate parts of them. Make them immutable and they are really easy to work with!
28 Answers
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TypeError: 'NoneType' object is not iterable in Python
... Correct, But the common scenario author intended here is totally to skip the for loop instead of raising an exception. Python's design is flawed here. When None is treated as an iterable it must return empty list at least. This exception never helped anyone in real life other than m...
warning: implicit declaration of function
...000/svg\"\u003e\u003cpath d=\"M46.1709 9.17788C46.1709 8.26454 46.2665 7.94324 47.1084 7.58816C47.4091 7.46349 47.7169 7.36433 48.0099 7.26993C48.9099 6.97997 49.672 6.73443 49.672 5.93063C49.672 5.22043 48.9832 4.61182 48.1414 4.61182C47.4335 4.61182 46.7256 4.91628 46.0943 5.50789C45.7307 4.9328 4...
Force CloudFront distribution/file update
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Good news. Amazon finally added an Invalidation Feature. See the API Reference.
This is a sample request from the API Reference:
POST /2010-08-01/distribution/[distribution ID]/invalidation HTTP/1.0
Host: cloudfront.amazonaws.com
Authorization:...
How to see which flags -march=native will activate?
I'm compiling my C++ app using GCC 4.3. Instead of manually selecting the optimization flags I'm using -march=native , which in theory should add all optimization flags applicable to the hardware I'm compiling on. But how can I check which flags is it actually using?
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...出现错误提示，缺少ld-linux.so.2:
是因为64位系统中安装了32位程序
解决方法：
yum install glibc.i686
再次运行 ant start
在测试时已经能进入网页https://服务器IP地址,但是用超级用户不能登录,重启下服务器即可
#reboot
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How do I create a copy of an object in PHP?
...ass by reference is a bad idea, because it makes the effect of a function call depend on the implementation of the function, rather than on the specification. It's got nothing to do with pass by value being the default.
– Oswald
Oct 4 '13 at 7:06
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