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Select multiple columns in data.table by their numeric indices
How can we select multiple columns using a vector of their numeric indices (position) in data.table ?
5 Answers
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Determine a string's encoding in C#
...igh probability) unicode files with the BOM/signature missing
Searches for charset=xyz and encoding=xyz inside file to help determine encoding.
To save processing, you can 'taste' the file (definable number of bytes).
The encoding and decoded text file is returned.
Purely byte-based solution for eff...
How to get TimeZone from android mobile?
...ndar.getInstance();
TimeZone tz = cal.getTimeZone();
It will return user selected timezone.
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How to get an object's property's value by property name?
...
Sure
write-host ($obj | Select -ExpandProperty "SomeProp")
Or for that matter:
$obj."SomeProp"
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How to simulate a button click using code?
...mes be a better choice in my experience than performClick(). If a user has selection sounds enabled, then performClick() could cause the user to hear two continuous selection sounds that are somewhat layered on top of each other which can be jarring. (One selection sound for the user's first button ...
关于php的socket初探 - PHP - 清泛IT论坛,有思想、有深度
...连接的模型都应该被称为多路复用,目前比较常用的有 select/poll/epoll/kqueue 这些 IO 模型(目前也有像 Apache 这种每个连接用单独的进程/线程来处理的 IO 模型,但是效率相对比较差,也很容易出问题,所以暂时不做介绍了)。在...
What is dynamic programming? [closed]
...er the three natural types of changes:
Substitution - change a single character from pattern "s" to a different character in text "t", such as changing "shot" to "spot".
Insertion - insert a single character into pattern "s" to help it match text "t", such as changing "ago" to "agog".
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Why should C++ programmers minimize use of 'new'?
...ts. std::string is a perfect example. This snippet:
int main ( int argc, char* argv[] )
{
std::string program(argv[0]);
}
actually allocates a variable amount of memory. The std::string object allocates memory using the heap and releases it in its destructor. In this case, you did not need ...
PreparedStatement with list of parameters in a IN clause [duplicate]
... possibleValue.size(); i++ ) {
builder.append("?,");
}
String stmt = "select * from test where field in ("
+ builder.deleteCharAt( builder.length() -1 ).toString() + ")";
PreparedStatement pstmt = ...
And then happily set the params
int index = 1;
for( Object o : possibleVal...
Delete multiple objects in django
I need to select several objects to be deleted from my database in django using a webpage. There is no category to select from so I can't delete from all of them like that. Do I have to implement my own delete form and process it in django or does django have a way to already do this? As its impleme...
