A simple python answer, ignores the 0 case:
x = [-0.01, 0.003, -0.002, 0.018, 0.002, 0.006, -0.012, 0.014, -0.017, -0.007, 0.002, 0.002, -0.004, 0.015, 0.002, -0.001, -0.008, 0.01, -0.018, 0.046]count = 0sign_positive = x[0] > 0sign_count = []for n in x: # the idea is to keep track of the sign and increment the # count if it agrees with the current number we are looking at if (n > 0 and sign_positive) or (n < 0 and not sign_positive): count = count + 1 # if it does not, the count goes back to 1 else: count = 1 # Whether we increased the count or not, we update whether the # sign was positive or negative sign_positive = n > 0 sign_count.append(count)# This is just to reproduce the output # (although I find the last repetition of the number unnecessary) results = list(zip(x, sign_count))for i, result in enumerate(results): print(f"{i: >2d} {result[0]: .3f} {result[1]: >2d} {result[0]: .3f}") 0 -0.010 1 -0.010 1 0.003 1 0.003 2 -0.002 1 -0.002 3 0.018 1 0.018 4 0.002 2 0.002 5 0.006 3 0.006 6 -0.012 1 -0.012 7 0.014 1 0.014 8 -0.017 1 -0.017 9 -0.007 2 -0.00710 0.002 1 0.00211 0.002 2 0.00212 -0.004 1 -0.00413 0.015 1 0.01514 0.002 2 0.00215 -0.001 1 -0.00116 -0.008 2 -0.00817 0.010 1 0.01018 -0.018 1 -0.01819 0.046 1 0.046A little more sophisticated solution, also takes care of the 0 case:
# To test the 0 case I am changing two numbers to 0x = [-0.01, 0.003, -0.002, 0.018, 0.002, 0.006, -0.012, 0.014, -0.017, -0.007, 0, 0, -0.004, 0.015, 0.002, -0.001, -0.008, 0.01, -0.018, 0.046]# The rest is similarcount = 0# This time we are using a nested ternary assignment # to account for the case of 0# This would be more readable as a function, # but what it does is simple# It returns None if n is 0, # True if it is larger than 0 # and False if it less than 0sign_positive = None if n == 0 else False if n < 0 else Truesign_count = []for n in x: # We add the case of 0 by adding a third condition where # sign_positive was None (meaning the previous # number was 0) and the current number is 0. if (n > 0 and sign_positive) or \ (n < 0 and not sign_positive) or \ (n == 0 and sign_positive == None): count = count + 1 else: count = 1 sign_positive = None if n == 0 else False if n < 0 else True sign_count.append(count)results = list(zip(x, sign_count))for i, result in enumerate(results): print(f"{i: >2d} {result[0]: .3f} {result[1]: >2d} {result[0]: .3f}") 0 -0.010 1 -0.010 1 0.003 1 0.003 2 -0.002 1 -0.002 3 0.018 1 0.018 4 0.002 2 0.002 5 0.006 3 0.006 6 -0.012 1 -0.012 7 0.014 1 0.014 8 -0.017 1 -0.017 9 -0.007 2 -0.00710 0.000 1 0.00011 0.000 2 0.00012 -0.004 3 -0.00413 0.015 1 0.01514 0.002 2 0.00215 -0.001 1 -0.00116 -0.008 2 -0.00817 0.010 1 0.01018 -0.018 1 -0.01819 0.046 1 0.046