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How do I get elapsed time in milliseconds in Ruby?
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Why use Abstract Base Classes in Python?
...sinstance(c, MyABC): # will be true
c.abc_method() # raises AttributeError
Unfortunately this one of those "just don't do that" traps (of which Python has relatively few!): avoid defining ABCs with both a __subclasshook__ and non-abstract methods. Moreover, you should make your definition of...
Why number 9 in kill -9 command in unix? [closed]
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The events can vary from user requests to illegal memory access
errors. Some signals, such as the interrupt signal, indicate that a
user has asked the program to do something that is not in the usual
flow of control.
There are several types of Signals we can use - to get a fu...
Popup弹出菜单扩展 · App Inventor 2 中文网
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可以使用哪些HTML标签取决于实现。您可以找到相关提示这里或这里。
图标名称
符号文件的名称指的是资源文件，即上传到AI2项目的文件。
可以省略”.png”或”.jpg”文件扩展名。扩展会自动搜索。名...
Can I install/update WordPress plugins without providing FTP access?
...b server runs) does not have proper write permissions, you will receive an error.
In summary, if you do not want to (or you cannot) change permissions on wp-content so your web server has write permissions, then add this to your wp-config.php file:
define('FS_METHOD', 'direct');
Permissions ex...
filename and line number of python script
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NameError: global name '__file__' is not defined on my Python interpreter: Python 2.7.6 (default, Sep 26 2014, 15:59:23). See stackoverflow.com/questions/9271464/…
– bgoodr
May 5 '17 at 17...
How to print out the method name and line number and conditionally disable NSLog?
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This code causes an unused variable error in Xcode 5.1 if not running in DEBUG :(
– yonix
Mar 18 '14 at 13:11
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How to make MySQL handle UTF-8 properly
... answer - You should almost always be using the utf8mb4 charset and utf8mb4_unicode_ci collation.
To alter database:
ALTER DATABASE dbname CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
See:
Aaron's comment on this answer How to make MySQL handle UTF-8 properly
What's the difference betwee...
What does mysql error 1025 (HY000): Error on rename of './foo' (errorno: 150) mean?
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You usually get this error if your tables use the InnoDB engine. In that case you would have to drop the foreign key, and then do the alter table and drop the column.
But the tricky part is that you can't drop the foreign key using the column na...
Base64 length calculation?
... use doubles because we don't want to use the floating point ops, rounding errors etc. They are just not necessary.
For this it is a good idea to remember how to perform the ceiling division: ceil(x / y) in doubles can be written as (x + y - 1) / y (while avoiding negative numbers, but beware of ov...