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Is it safe to resolve a promise multiple times?
... rejected), that is it for a defered object - it is done.
If you should call then(...) on it's promise again, you should immediately get the (first) resolved/rejected result.
Additional calls to resolve() will not (should not?) have any effect. Not sure what happens if you attempt to reject a de...
When should I use uuid.uuid1() vs. uuid.uuid4() in python?
...d4() generates, as you said, a random UUID. The chance of a collision is really, really, really small. Small enough, that you shouldn't worry about it. The problem is, that a bad random-number generator makes it more likely to have collisions.
This excellent answer by Bob Aman sums it up nicely. (I...
What are file descriptors, explained in simple terms?
...you open a network socket, it is also represented by an integer and it is called Socket Descriptor.
I hope you understand.
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What is Weak Head Normal Form?
... further (i.e. it contains no un-evaluated thunks).
These expressions are all in normal form:
42
(2, "hello")
\x -> (x + 1)
These expressions are not in normal form:
1 + 2 -- we could evaluate this to 3
(\x -> x + 1) 2 -- we could apply the function
"he" ++ "llo" ...
How to export all data from table to an insertable sql format?
I have a Table (call it A_table ) in a database (call it A_db ) in Microsoft SQL Server Management Studio, and there are 10 rows.
...
Python: finding an element in a list [duplicate]
...hod .index.
For the objects in the list, you can do something like:
def __eq__(self, other):
return self.Value == other.Value
with any special processing you need.
You can also use a for/in statement with enumerate(arr)
Example of finding the index of an item that has value > 100.
for...
Determine if Android app is being used for the first time
...
Beware for Android 6.0 (API 23 - Marshmallow) or above auto backup (developer.android.com/guide/topics/data/autobackup.html)is enabled by default. If the users uninstalls and then reinstalls the app the shared preferences will be recovered. So on reinstalls you ca...
How do you implement a class in C? [closed]
...se C (no C++ or object oriented compilers) and I don't have dynamic memory allocation, what are some techniques I can use to implement a class, or a good approximation of a class? Is it always a good idea to isolate the "class" to a separate file? Assume that we can preallocate the memory by assumin...
Detecting when the 'back' button is pressed on a navbar
...to work under certain scenarios in iOS 8+. I can't verify that that is actually the case without further details.
For those of you however in that situation there's an alternative. Detecting when a view controller is being popped is possible by overriding willMove(toParentViewController:). The basi...
How to create a drop-down list?
...iew:
XML:
<Spinner
android:id="@+id/spinner1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@android:drawable/btn_dropdown"
android:spinnerMode="dropdown"/>
Java:
//get the spinner from the xml.
Spinner dropdown = findVi...