大约有 40,000 项符合查询结果（耗时：0.0460秒） [XML]
MySQL Orderby a number, Nulls last
... tablename WHERE visible=1 ORDER BY -position DESC, id DESC
It is essentially the inverse of position DESC placing the NULL values last but otherwise the same as position ASC.
A good reference is here http://troels.arvin.dk/db/rdbms#select-order_by
...
Decoding and verifying JWT token using System.IdentityModel.Tokens.Jwt
...
Within the package there is a class called JwtSecurityTokenHandler which derives from System.IdentityModel.Tokens.SecurityTokenHandler. In WIF this is the core class for deserialising and serialising security tokens.
The class has a ReadToken(String) method tha...
What is a lambda (function)?
...us and refers to anonymous functions in programming.
Why is this cool? It allows you to write quick throw away functions without naming them. It also provides a nice way to write closures. With that power you can do things like this.
Python
def adder(x):
return lambda y: x + y
add5 = adder(5)...
Current time in microseconds in java
...ble on many platforms, 2) returning millisecond accuracy in a microsecond call leads to application portability issues.
– Stephen C
Nov 11 '09 at 4:17
9
...
Glorified classes in the Java language
... lot of different answers, so I thought it would be useful to collect them all (and add some):
Classes
AutoBoxing classes - the compiler only allows for specific classes
Class - has its own literals (int.class for instance). I would also add its generic typing without creating new instances.
Stri...
Convert UTC datetime string to local datetime
... this. The dateutil.zoneinfo module I was showing previously is used internally by the tz module as a fall back if it can't locate the system's zoneinfo DB. If you look inside the library you'll see that there's a zoneinfo DB tarball in the package that it uses if it can't find your system's DB. My...
LINQ: Distinct values
...
Oh so by "larger type" you may mean I still want all properties in the result even though I only want to compare a few properties to determine distinctness?
– The Red Pea
Sep 20 '16 at 14:31
...
How to create a GUID/UUID using iOS
...tring = CFUUIDCreateString(NULL, theUUID);
CFRelease(theUUID);
return (__bridge NSString *)string;
}
EDIT: Jan, 29 2014:
If you're targeting iOS 6 or later, you can now use the much simpler method:
NSString *UUID = [[NSUUID UUID] UUIDString];
...
Property getters and setters
...g to backup the computed property. Try this:
class Point {
private var _x: Int = 0 // _x -> backingX
var x: Int {
set { _x = 2 * newValue }
get { return _x / 2 }
}
}
Specifically, in the Swift REPL:
15> var pt = Point()
pt: Point = {
_x = 0
}
16> pt.x = 10...
Unique fields that allow nulls in Django
...pty string by providing your own customized model form for Foo with a clean_bar method that turns the empty string into None:
class FooForm(forms.ModelForm):
class Meta:
model = Foo
def clean_bar(self):
return self.cleaned_data['bar'] or None
class FooAdmin(admin.ModelAdmin...