大约有 41,000 项符合查询结果（耗时：0.0587秒） [XML]
Providing a default value for an Optional in Swift?
The idiom for dealing with optionals in Swift seems excessively verbose, if all you want to do is provide a default value in the case where it's nil:
...
Detecting an undefined object property
... check if an object does not actually have such a property, and will therefore return undefined by default when you try and access it:
if(!o.hasOwnProperty('myProperty')) {
alert("myProperty does not exist");
}
To check if the value associated with an identifier is the special value undefined, ...
Start service in Android
...
Probably you don't have the service in your manifest, or it does not have an <intent-filter> that matches your action. Examining LogCat (via adb logcat, DDMS, or the DDMS perspective in Eclipse) should turn up some warnings that may help.
More likely, you should start th...
git --git-dir not working as expected
I am trying to run git from a different directory than I am in. So for example if I am in:
4 Answers
...
How can I loop through a C++ map of maps?
...e remaining answers are outdated as of C++11 - you can use a ranged based for loop and simply do:
std::map<std::string, std::map<std::string, std::string>> mymap;
for(auto const &ent1 : mymap) {
// ent1.first is the first key
for(auto const &ent2 : ent1.second) {
// ent...
Is it a bad practice to catch Throwable?
...
You need to be as specific as possible. Otherwise unforeseen bugs might creep away this way.
Besides, Throwable covers Error as well and that's usually no point of return. You don't want to catch/handle that, you want your program to die immediately so that you can fix it prop...
Using Mockito with multiple calls to the same method with the same arguments
...tions? I'd like to do this to test nondeterminate responses from an ExecutorCompletionService . i.e. to test that irrespective of the return order of the methods, the outcome remains constant.
...
What's the difference between parenthesis $() and curly bracket ${} syntax in Makefile?
... any differences in invoking variables with syntax ${var} and $(var) ? For instance, in the way the variable will be expanded or anything?
...
Cookie blocked/not saved in IFRAME in Internet Explorer
...therexample.net/page.html , I have an IFRAME SRC="http://example.com/someform.asp" . That IFRAME displays a form for the user to fill out and submit to http://example.com/process.asp . When I open the form (" someform.asp ") in its own browser window, all works well.
However, when I load someform...
Greedy vs. Reluctant vs. Possessive Quantifiers
I found this excellent tutorial on regular expressions and while I intuitively understand what "greedy", "reluctant" and "possessive" quantifiers do, there seems to be a serious hole in my understanding.
...