大约有 36,030 项符合查询结果（耗时：0.0468秒） [XML]
How to get last N records with activerecord?
..., so you could let ruby sort it at at that time. (ie. records.reverse.each do ..)
– Dan McNevin
Jan 7 '09 at 14:25
Alt...
Eloquent Collection: Counting and Detect Empty
...ch will always return true.
To determine if there are any results you can do any of the following:
if ($result->first()) { }
if (!$result->isEmpty()) { }
if ($result->count()) { }
if (count($result)) { }
You could also use ->first() instead of ->get() on the query builder which w...
Objective-C: difference between id and void *
...
void * means "a reference to some random chunk o' memory with untyped/unknown contents"
id means "a reference to some random Objective-C object of unknown class"
There are additional semantic differences:
Under GC Only or GC Supported modes, the compiler wil...
When to use an interface instead of an abstract class and vice versa?
This may be a generic OOP question. I wanted to do a generic comparison between an interface and an abstract class on the basis of their usage.
...
Intercept page exit event
...ithin my system, a user might decide to navigate to another website and in doing so could lose all the edits they have not saved.
...
Xcode 5: Code signing entitlement errors
...de signing identity at the top level row of each, using the Combined view. Doing so still snapped it back to <Multiple values>. When I expanded both rows, however, I saw the "Any iOS SDK" subrows for each configuration all set to None, although the Debug/Release rows did list the proper profil...
How do I get and set Environment variables in C#?
...stem.Environment.SetEnvironmentVariable(variable, value [, Target])
will do the job for you.
The optional parameter Target is an enum of type EnvironmentVariableTarget and it can be one of: Machine, Process, or User. If you omit it, the default target is the current process.
...
Is there a way of setting culture for a whole application? All current threads and new threads?
...reInfo.DefaultThreadCurrentCulture property to change the culture of an AppDomain.
For versions prior to 4.5 you have to use reflection to manipulate the culture of an AppDomain. There is a private static field on CultureInfo (m_userDefaultCulture in .NET 2.0 mscorlib, s_userDefaultCulture in .NET...
How do I define and use an ENUM in Objective-C?
... in my methods. But I am getting errors stating that it is undeclared. How do I correctly declare and use a variable of type PlayerState in my methods?:
...
Is it possible to read the value of a annotation in java?
...etention(RetentionPolicy.RUNTIME)
@interface Column {
....
}
you can do something like this
for (Field f: MyClass.class.getFields()) {
Column column = f.getAnnotation(Column.class);
if (column != null)
System.out.println(column.columnName());
}
UPDATE : To get private fields us...