大约有 12,000 项符合查询结果（耗时：0.0271秒） [XML]
Why check both isset() and !empty()
...
This is completely redundant. empty is more or less shorthand for !isset($foo) || !$foo, and !empty is analogous to isset($foo) && $foo. I.e. empty does the reverse thing of isset plus an additional check for the truthiness of a value.
Or in other words, empty is the same as !$foo, but d...
Casting to string in JavaScript
...ut you can cast undefined to a string using the other two methods:
var foo;
var myString1 = String(foo); // "undefined" as a string
var myString2 = foo + ''; // "undefined" as a string
var myString3 = foo.toString(); // throws an exception
http://jsfiddle.net/f8YwA/
...
How do I test a private function or a class that has private methods, fields or inner classes?
...essible member, is via @Jailbreak from the Manifold framework.
@Jailbreak Foo foo = new Foo();
// Direct, *type-safe* access to *all* foo's members
foo.privateMethod(x, y, z);
foo.privateField = value;
This way your code remains type-safe and readable. No design compromises, no overexposing ...
Java Class.cast() vs. cast operator
... special to the compiler. It could be optimized when used statically (i.e. Foo.class.cast(o) rather than cls.cast(o)) but I've never seen anybody using it - which makes the effort of building this optimization into the compiler somewhat worthless.
...
What's the difference between `on` and `live` or `bind`?
...(or live)...
So in practice, you can:
Use on like bind:
/* Old: */ $(".foo").bind("click", handler);
/* New: */ $(".foo").on("click", handler);
Use on like delegate (event delegation rooted in a given element):
/* Old: */ $("#container").delegate(".foo", "click", handler);
/* New: */ $("#conta...
How to use XPath in Python?
... node set size"
sys.exit(1)
if res[0].name != "doc" or res[1].name != "foo":
print "xpath query: wrong node set value"
sys.exit(1)
doc.freeDoc()
ctxt.xpathFreeContext()
Sample of ElementTree XPath Use
from elementtree.ElementTree import ElementTree
mydoc = ElementTree(file='tst.xml'...
How to quickly clear a JavaScript Object?
... to Object.observe in ES7 and with data-binding in general. Consider:
var foo={
name: "hello"
};
Object.observe(foo, function(){alert('modified');}); // bind to foo
foo={}; // You are no longer bound to foo but to an orphaned version of it
foo.name="there"; // This change will be missed by Obj...
Does Swift have access modifiers?
...
protocol MyClass {
var publicProperty:Int {get set}
func publicMethod(foo:String)->String
}
class MyClassImplementation : MyClass {
var publicProperty:Int = 5
var privateProperty:Int = 8
func publicMethod(foo:String)->String{
return privateMethod(foo)
}
func privateMethod...
“Invalid JSON primitive” in Ajax processing
...avaScriptSerializer.serialize(obj);?
If it is a valid json object like {'foo':'foovalue', 'bar':'barvalue'} then jQuery might not send it as json data but instead serialize it to foor=foovalue&bar=barvalue thus you get the error "Invalid JSON primitive: foo"
Try instead setting the data as st...
Why avoid increment (“++”) and decrement (“--”) operators in JavaScript?
...ways use ++ and -- by themselves on a single line, as in:
i++;
array[i] = foo;
instead of
array[++i] = foo;
Anything beyond that can be confusing to some programmers and is just not worth it in my view. For loops are an exception, as the use of the increment operator is idiomatic and thus alw...