大约有 41,000 项符合查询结果（耗时：0.0319秒） [XML]
How can I group by date time column without taking time into consideration
...
Cast/Convert the values to a Date type for your group by.
GROUP BY CAST(myDateTime AS DATE)
share
|
improve this answer
...
How do I convert a string to a number in PHP?
...mstances. For situations where you do want to explicitly convert the type, cast it:
$num = "3.14";
$int = (int)$num;
$float = (float)$num;
share
|
improve this answer
|
fol...
How can I convert a long to int in Java?
...ted, in Java 8:
Math.toIntExact(value);
Original Answer:
Simple type casting should do it:
long l = 100000;
int i = (int) l;
Note, however, that large numbers (usually larger than 2147483647 and smaller than -2147483648) will lose some of the bits and would be represented incorrectly.
For ...
How do I make the method return type generic?
...nimal> T callFriend(String name, Class<T> type) {
return type.cast(friends.get(name));
}
Then call it as such:
jerry.callFriend("spike", Dog.class).bark();
jerry.callFriend("quacker", Duck.class).quack();
This code has the benefit of not generating any compiler warnings. Of course ...
How can I output the value of an enum class in C++11
...ts integer value. You need to explicitly convert it to an integer using a cast:
std::cout << static_cast<std::underlying_type<A>::type>(a) << std::endl;
You may want to encapsulate the logic into a function template:
template <typename Enumeration>
auto as_integer(...
How can I convert a std::string to int?
...stinguish between bad input (see here).
4. Fourth option: Boost's lexical_cast
#include <boost/lexical_cast.hpp>
#include <string>
std::string str;
try {
int i = boost::lexical_cast<int>( str.c_str());
float f = boost::lexical_cas...
Performance surprise with “as” and nullable types
...d is of the expected type, takes but a few machine code instructions. The cast is also easy, the JIT compiler knows the location of the value bits in the object and uses them directly. No copying or conversion occurs, all machine code is inline and takes but about a dozen instructions. This neede...
C++ equivalent of java's instanceof
...
Try using:
if(NewType* v = dynamic_cast<NewType*>(old)) {
// old was safely casted to NewType
v->doSomething();
}
This requires your compiler to have rtti support enabled.
EDIT:
I've had some good comments on this answer!
Every time you need...
Enum String Name from Value
...
You can convert the int back to an enumeration member with a simple cast, and then call ToString():
int value = GetValueFromDb();
var enumDisplayStatus = (EnumDisplayStatus)value;
string stringValue = enumDisplayStatus.ToString();
...
How does std::move() transfer values into RValues?
...reference<T>::type&& move(T&& arg)
{
return static_cast<typename remove_reference<T>::type&&>(arg);
}
Let's start with the easier part - that is, when the function is called with rvalue:
Object a = std::move(Object());
// Object() is temporary, which ...