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foldl versus foldr behavior with infinite lists
...r folding a list of n values [x1, x2, x3, x4 ... xn ] with some function f and seed z.
foldl is:
Left associative: f ( ... (f (f (f (f z x1) x2) x3) x4) ...) xn
Tail recursive: It iterates through the list, producing the value afterwards
Lazy: Nothing is evaluated until the result is needed
Backw...
How to use WinForms progress bar?
...groundWorker. If you have a loop that large in your WinForm it will block and your app will look like it has hanged.
Look at BackgroundWorker.ReportProgress() to see how to report progress back to the UI thread.
For example:
private void Calculate(int i)
{
double pow = Math.Pow(i, i);
}
pri...
How do I insert datetime value into a SQLite database?
...
When you format dates like this, date ordering and lexical ordering work out the same. E.g. '2008-02-01' > '2007-02-01', '2008-01-02' > '2008-01-01' both as strings and as dates. But you don't strictly need to care about this because SQLite ORDER BY will take care ...
When vectors are allocated, do they use memory on the heap or the stack?
... store.
vector<Type*> vect;
will allocate the vector on the stack and a bunch of pointers on the free store, but where these point is determined by how you use them (you could point element 0 to the free store and element 1 to the stack, say).
...
Mismatch Detected for 'RuntimeLibrary'
I downloaded and extracted Crypto++ in C:\cryptopp. I used Visual Studio Express 2012 to build all the projects inside (as instructed in readme), and everything was built successfully. Then I made a test project in some other folder and added cryptolib as a dependency. After that, I added the includ...
Extracting substrings in Go
...
It looks like you're confused by the working of slices and the string storage format, which is different from what you have in C.
any slice in Go stores the length (in bytes), so you don't have to care about the cost of the len operation : there is no need to count
Go strings a...
What's the optimum way of storing an NSDate in NSUserDefaults?
...t primitive)? Just [sharedDefaults setObject:theDate forKey:@"theDateKey"] and be done with it. NSDate is one of the "main types" supported by the PLIST format (dates, numbers, strings, data, dictionaries, and arrays), so you can just store it directly.
See the documentation for proof.
Just store ...
What exactly is Heroku?
I just started learning Ruby on rails and I was wondering what Heroku really is? I know that its a cloud that helps us to avoid using servers? When do we actually use it?
...
How to return an empty ActiveRecord relation?
If I have a scope with a lambda and it takes an argument, depending on the value of the argument, I might know that there will not be any matches, but I still want to return a relation, not an empty array:
...
Comparing two NumPy arrays for equality, element-wise
... all values of array (A==B) are True.
Note: maybe you also want to test A and B shape, such as A.shape == B.shape
Special cases and alternatives (from dbaupp's answer and yoavram's comment)
It should be noted that:
this solution can have a strange behavior in a particular case: if either A or B...