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What is an optional value in Swift?
...ny type:
var name: String? = "Bertie"
Optionals (along with Generics) are one of the most difficult Swift concepts to understand. Because of how they are written and used, it's easy to get a wrong idea of what they are. Compare the optional above to creating a normal String:
var name: String = "Ber...
How to get the Android device's primary e-mail address
...be
// a primary email address if the user hasn't specified one.
ContactsContract.Contacts.Data.IS_PRIMARY + " DESC");
}
@Override
public void onLoadFinished(Loader<Cursor> cursorLoader, Cursor cursor) {
List<String> emails = new ArrayL...
difference between throw and throw new Exception()
... "throw new Exception(ex); is even worse.": I disagree on this one. Sometimes you want to change the type of an exception, and then keeping the original exception as inner exception is the best you can do. Though it should be throw new MyCustomException(myMessage, ex); of course.
...
How many concurrent AJAX (XmlHttpRequest) requests are allowed in popular browsers?
...mlHttpRequest (on any tab) to the same domain is fired, it is queued until one of the other 6 finish.
8 Answers
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Use JNI instead of JNA to call native code?
...d a jni wrapper
If you need a lot of memory copying. For example, you call one method which returns you a large byte buffer, you change something in it, then you need to call another method which uses this byte buffer. This would require you to copy this buffer from c to java, then copy it back from...
Update value of a nested dictionary of varying depth
...idea, i.e. a recursive solution, but somewhat peculiar coding and at least one bug. I'd recommend, instead:
Python 2:
import collections
def update(d, u):
for k, v in u.iteritems():
if isinstance(v, collections.Mapping):
d[k] = update(d.get(k, {}), v)
else:
...
Equivalent C++ to Python generator pattern
... State { unsigned i, j; };
State make();
void next(State&);
bool isDone(State const&);
Of course, we wrap this as a proper class:
class PairSequence:
// (implicit aliases)
public std::iterator<
std::input_iterator_tag,
std::pair<unsigned, unsigned>
...
What are dictionary view objects?
... as well. This feature can be useful in some circumstances (for instance, one can work with a view on the keys in multiple parts of a program instead of recalculating the current list of keys each time they are needed)—note that if the dictionary keys are modified while iterating over the view, h...
Casting vs using the 'as' keyword in the CLR
...n. That throws an exception immediately, which means that no more work is done under incorrect assumptions, and the exception correctly shows the type of bug.
// This will throw an exception if randomObject is non-null and
// refers to an object of an incompatible type. The cast is
// the best code...
How can I redirect the output of the “time” command?
...will take the arguments as a command. But parenthesis will group that as a one command. Ex: time ls > file1.txt In arguments, 0 = time 1 = "ls > file1.txt"
– sganesh
Mar 9 '10 at 12:49
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