大约有 44,000 项符合查询结果（耗时：0.0457秒） [XML]
How to make a great R reproducible example
... X73 Class
1 A 266 960 Yes
2 A 373 315 No Notice the selection split
3 A 573 208 No (which can be turned off)
4 A 907 850 Yes
5 B 202 46 Yes
6 B 895 969 Yes <~~~ 70 % of selection is from the top rows
7 B 940 928 No
98 Y 37...
Is there a query language for JSON?
...joined items
.equals("location.state", "TX")
//and even do custom selections
.select(function(rec) {
return {
fullname : rec.firstname + " " + rec.lastname,
city : rec.location.city,
ageInTenYears : (rec.age + 10)
};
});
It's ful...
How do I rename a column in a database table using SQL?
...any other RDBMS), you can do it with regular ALTER TABLE statement:
=> SELECT * FROM Test1;
id | foo | bar
----+-----+-----
2 | 1 | 2
=> ALTER TABLE Test1 RENAME COLUMN foo TO baz;
ALTER TABLE
=> SELECT * FROM Test1;
id | baz | bar
----+-----+-----
2 | 1 | 2
...
Find difference between timestamps in seconds in PostgreSQL
...
Try:
SELECT EXTRACT(EPOCH FROM (timestamp_B - timestamp_A))
FROM TableA
Details here: EXTRACT.
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Guaranteed lifetime of temporary in C++?
... {
if (m_buffer.size() != 0)
{
size_t l = std::char_traits<C>::length(get());
m_str.assign(get(), l);
m_buffer.resize(0);
}
}
void abort()
{ m_buffer.resize(0); }
};
template <class C>
inline _StringBuffer&...
How to determine MIME type of file in android?
...
If the media is selected from android gallery then TYPE is returned. If selected from File Manager then null is returned.
– Rahul Rastogi
Aug 27 '14 at 12:34
...
How to get default gateway in Mac OSX
...the first line; one with default at its first column.
To display only the selected lines of result, we can use grep command along with netstat
netstat -rn | grep 'default'
This command filters and displays those lines of result having default. In this case, you can see result like following:
de...
Parallel.ForEach() vs. foreach(IEnumerable.AsParallel())
...the AsParallel() call, like:
var fibonacciNumbers = numbers.AsParallel().Select(n => ComputeFibonacci(n));
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How to generate the JPA entity Metamodel?
...EE Developers") has its own metamodel generator integrated with Eclipse.
Select your project in the Package Explorer
Go to Properties -> JPA dialog
Select source folder from Canonical metamodel (JPA 2.0) group
Click Apply button to generate metamodel classes in the selected source folder
Th...
Convert dictionary to list collection in C#
...
To convert the Keys to a List of their own:
listNumber = dicNumber.Select(kvp => kvp.Key).ToList();
Or you can shorten it up and not even bother using select:
listNumber = dicNumber.Keys.ToList();
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