Stef Mientki wrote: > Does anyone know the equivalent of the MatLab "diff" function. > The "diff" functions calculates the difference between 2 succeeding > elements of an array. > I need to detect (fast) the falling edge of a binary signal.
Using numpy (or predecessors), you can do this easily with slicing: a[1:] - a[:-1] Slicing shares data, so the slices above don't create new arrays, but new views into the old array, so it avoids that overhead. For Python lists you'd have to use a list comprehension or some such thing like that. For example: [ x-y for (x,y) in zip(a[1:],a[:-1]) ] Or, to avoid creating two new arrays, use iterators: import itertools [ x-y for (x,y) in itertools.izip(itertools.islice(a,0,-1),itertools.islice(a,1)) ] Carl -- http://mail.python.org/mailman/listinfo/python-list
