def angle ( x , y ) : return arccos ( dot ( x , y ) / ( norm ( x ) * norm ( y ) ) ) * 180. / pi
python angle from three points
Return the angle between vectors a and b in degrees .
def angle(x, y):
    """Return the angle between vectors a and b in degrees."""
    return arccos(dot(x, y)/(norm(x)*norm(y)))*180./pi