大约有 44,000 项符合查询结果（耗时：0.0612秒） [XML]
Understanding implicit in Scala
...
In scala implicit works as:
Converter
Parameter value injector
Extension method
There are 3 types of use of Implicit
Implicitly type conversion : It converts the error producing assignment into intended type
val x :String = "1"
val y:Int = x
String...
postgresql - sql - count of `true` values
...his works:
SELECT count(*) AS total
, sum(myCol::int) AS countTrue --convert Boolean to Integer
FROM yourTable
;
or better (to avoid :: and use standard SQL syntax):
SELECT count(*) AS total
, sum(CAST(myCol AS int)) AS countTrue --convert Boolean to Integer
FROM yourTable
;
...
Fastest way to determine if an integer's square root is an integer
...
Wow! I'll try to convert this to Java and do a comparison, as well as an accuracy check on the results. I'll let you know what I find.
– Kip
Jan 12 '09 at 21:47
...
How to export DataTable to Excel
...
Try simple code, to convert DataTable to excel file as csv:
var lines = new List<string>();
string[] columnNames = dataTable.Columns
.Cast<DataColumn>()
.Select(column => column.ColumnName)
.ToArray();
var header = ...
Generate a random date between two other dates
...
Convert both strings to timestamps (in your chosen resolution, e.g. milliseconds, seconds, hours, days, whatever), subtract the earlier from the later, multiply your random number (assuming it is distributed in the range [0, ...
Why can't I use float value as a template parameter?
... character pack template<char ...cs>, then the string literal can be converted into such a pack at compile time. Here is a demo on ideone. (Demo is C++14, but it's easy to port it back to C++11 - std::integer_sequence is the only difficulty)
– Aaron McDaid
...
In Functional Programming, what is a functor?
...fmap even
is an overloaded function that can do many wonderful things:
Convert a list of integers to a list of Booleans
Convert a tree of integers to a tree of Booleans
Convert Nothing to Nothing and Just 7 to Just False
In Haskell, this property is expressed by giving the type of fmap:
fmap ...
How to properly check if std::function is empty in C++11?
... an empty lambda doesn't really make sense. Behind the scenes the compiler converts a lambda expression into a struct (or class) definition, with the variables you capture stored as data members of this struct. A public function call operator is also defined, which is what allows you to invoke the l...
Algorithm to get the excel-like column name of a number
I'm working on a script that generate some Excel documents and I need to convert a number into its column name equivalent. For example:
...
Default template arguments for function templates
...
On Windows, with all versions of Visual Studio you can convert this error (C4519) to a warning or disable it like so:
#ifdef _MSC_VER
#pragma warning(1 : 4519) // convert error C4519 to warning
// #pragma warning(disable : 4519) // disable error C4519
#endif
See more details ...