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Mean per group in a data.frame [duplicate]
..."Rate2"), row.names = c(NA, -9L), class = c("data.table", "data.frame"))
Now to take the mean of Rate1 and Rate2 for all 3 months, for each person (Name):
First, decide which columns you want to take the mean of
colstoavg <- names(mydt)[3:4]
Now we use lapply to take the mean over the column...
Inversion of Control vs Dependency Injection
...l end up mixing responsibilities of classes, our (UIHandler) should never know about the concrete implementation of (SMSService), this should be done outside the classes using “Interfaces”. When this is implemented, it will give us the ability to change the behavior of the system by swapping the...
How to determine if a list of polygon points are in clockwise order?
...t a handful of large values could outweigh a large number of small values. Now consider arcsin of each value vs not. Isn't it still the case that failing to take arcsin gives incorrect weight to each value, therefore has same flaw (though much less so)?
– ToolmakerSteve
...
Can Flask have optional URL parameters?
...uess that you want to write a single route and mark username as optional? If that's the case, I don't think it's possible.
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扫码寻宝 · App Inventor 2 中文网
...始、App 启动，三个地方都要用。
procedure 显示线索() {
if 关卡 > length(线索) {
标签_关卡.Text = "全部通关！"
标签_线索.Text = "恭喜你找到了所有宝藏！"
} else {
标签_关卡.Text = join("第 ", 关卡, " 关 / 共 ", length(线索), " 关...
Encode String to UTF-8
...
String objects in Java use the UTF-16 encoding that can't be modified.
The only thing that can have a different encoding is a byte[]. So if you need UTF-8 data, then you need a byte[]. If you have a String that contains unexpected data, then the problem is at some earlier place that inco...
What Process is using all of my disk IO
If I use "top" I can see what CPU is busy and what process is using all of my CPU.
7 Answers
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Why do we need a pure virtual destructor in C++?
...class Base
{
public:
Base();
virtual ~Base() = 0; // Pure virtual, now no one can create the Base Object directly
};
Base::Base() { cout << "Base Constructor" << endl; }
Base::~Base() { cout << "Base Destructor" << endl; }
class Derived : public Base
{
public:
...
Determine if 2 lists have the same elements, regardless of order? [duplicate]
...o be hashable; runtime will be in O(n), where n is the size of the lists.
If the elements are also unique, you can also convert to sets (same asymptotic runtime, may be a little bit faster in practice):
set(x) == set(y)
If the elements are not hashable, but sortable, another alternative (runtime...
Where is a complete example of logging.config.dictConfig?
...'INFO',
'propagate': False
},
'__main__': { # if __name__ == '__main__'
'handlers': ['default'],
'level': 'DEBUG',
'propagate': False
},
}
}
Usage:
# Run once at startup:
logging.config.dictConfig(LOGGING_CONFIG)
# Inc...