Numpy.piecewise 条件/函数数量作为变量

Question

n = len(x_coords) conditions = [x_coords[i] <= x <= x_coords[i+1] for i in range(n-1)] functions = [f(x,i) for i in range(n-1)] def g(x): return np.piecewise(x, conditions, functions)

'x_coords' is just a list of x_coordinates between which I define different functions

When I run this code I get the error “'<=' not supported between instances of 'float' and 'list' ”

I think I know what the problem is - that the elements in the lists I create are statements rather than values. However, I don't know how to get around this as I need a list of condition statements and functions for the

np.piecewise

function parameters

Answer 1

Just use np.arrays instead of a list as this operation is not defined for built-in list. do:

 x_coords = np.array(x_coords)

You also may need to split the conditions:

 conditions = [ (x_coords[i] <= x) & (x <= x_coords[i+1]) for i in range(n-1)]