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ERROR 1396 (HY000): Operation CREATE USER failed for 'jack'@'localhost'
...be stupid" and to use REVOKE and DROP USER to do it right. I'm indebted to all three answers (this one just happens to be the one that bailed me out of my present predicament).
– Russ Bateman
Apr 5 '11 at 17:05
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Applying a function to every row of a table using dplyr?
...it reflects the fact that when you're doing row wise operations you're actually working with tuples from a list of vectors (the columns in a dataframe).
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Sleep for milliseconds
... facilities:
#include <chrono>
#include <thread>
std::this_thread::sleep_for(std::chrono::milliseconds(x));
Clear and readable, no more need to guess at what units the sleep() function takes.
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select、poll、epoll之间的区别总结[整理] - C/C++ - 清泛网 - 专注C/C++及内核技术
...1、select实现
select的调用过程如下所示：
（1）使用copy_from_user从用户空间拷贝fd_set到内核空间
（2）注册回调函数__pollwait
（3）遍历所有fd，调用其对应的poll方法（对于socket，这个poll方法是sock_poll，sock_poll根据情况会调用到...
eclipse won't start - no java virtual machine was found
Eclipse was running fine yesterday (and has been since I installed it about a year ago). Now all the sudden I'm getting the following error on startup:
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C++ Convert string (or char*) to wstring (or wchar_t*)
...f8_source_string);
Longer online compilable and runnable example:
(They all show the same example. There are just many for redundancy...)
http://ideone.com/KA1oty
http://ide.geeksforgeeks.org/5pRLSh
http://rextester.com/DIJZK52174
Note (old):
As pointed out in the comments and explained in h...
max value of integer
...hine to machine, on embedded systems the int can be 16 bit wide, though usually it is 32 bit.
The only requirement is that short int <= int <= long int by size. Also, there is a recommendation that int should represent the native capacity of the processor.
All types are signed. The unsigned...
Testing two JSON objects for equality ignoring child order in Java
...ary that supports comparing two JSON objects ignoring child order, specifically for unit testing JSON returning from a web service.
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List comprehension: Returning two (or more) items for each item
...bda x: x + 2
>>> g = lambda x: x ** 2
>>> list(chain.from_iterable((f(x), g(x)) for x in range(3)))
[2, 0, 3, 1, 4, 4]
Timings:
from timeit import timeit
f = lambda x: x + 2
g = lambda x: x ** 2
def fg(x):
yield f(x)
yield g(x)
print timeit(stmt='list(chain.from_itera...
Python date string to date object
...<stdin>", line 1, in <module>
File "/usr/local/lib/python2.7/_strptime.py", line 308, in _strptime
format_regex = _TimeRE_cache.compile(format)
File "/usr/local/lib/python2.7/_strptime.py", line 265, in compile
return re_compile(self.pattern(format), IGNORECASE)
File "/usr/...