stack

Suppose I have a data.table where each row consists of two vectors: A 'pre-subtraction' vector. A 'post-subtraction' vector. The pre-subtraction is the left-half most column and the post- is the right-most columns, with the suffix "prm" at the end. For example: #Sample Data set.seed(2) fill = data.table(n=1:7) Tp=3 for(t in 1:Tp){ set(x = fill, j = paste0('v',t), value = sample(0:10,7)) } fill[1,paste0('v',3):=0] fill[5,paste0('v',2):=0] fill[5,paste0('v',3):=0] for(t in 1:Tp){ fill[,paste0('v',t,'prm'):=get(paste0('v',t))] } fill[1,paste0('v',1,'prm'):=0] fill[2,paste0('v',2,'prm'):=1] fill[5

I've recently been implementing a recursive directory search implementation and I'm using a Stack to track the path elements. When I used string.Join() to join the path elements, I found that they were reversed. When I debugged the method, I looked into the stack and found that the elements themselves were reversed in the Stack's internal array, ie the most recently Push()ed element was at the beginning of the internal array, and the least recently Push()ed element was at the end of the internal array. This seems ass-backward and very counter-intuitive. Can somebody please tell me why

If I understand correctly the stack is for local primities and references to the objects in the heap. So what happens if you have more than one threads? Do they share the same stack space at the same time (but different areas) or does the JRE switch contexts and load-deload the stack content when switching between threads? Or does the JRE allocate separate stacks for each threads? Or does the JRE allocate separate stacks for each threads? Conceptually yes. (See this JVM spec link , for example.) How the spec's conceptualization gets implemented in a particular JVM is ... implementation

I'm trying to determine how much stack memory each method consumes when running. To do the task, I've devised this simple program that will just force a StackOverflowError , public class Main { private static int i = 0; public static void main(String[] args) { try { m(); } catch (StackOverflowError e) { System.err.println(i); } } private static void m() { ++i; m(); } } printing an integer telling me how many times m() was called. I've manually set the JVM's stack size( -Xss VM parameter) to varying values (128k, 256k, 384k), obtaining the following values: stack i delta 128 1102 256 2723 1621

Is there a numpy method which is equivalent to the builtin pop for python lists? Popping obviously doesn't work on numpy arrays, and I want to avoid a list conversion. There is no pop method for NumPy arrays, but you could just use basic slicing (which would be efficient since it returns a view, not a copy): In [104]: y = np.arange(5); y Out[105]: array([0, 1, 2, 3, 4]) In [106]: last, y = y[-1], y[:-1] In [107]: last, y Out[107]: (4, array([0, 1, 2, 3])) If there were a pop method it would return the last value in y and modify y . Above, last, y = y[-1], y[:-1] assigns the last value to the