Normalised correlation of two lists

#Returns the normalised correlation (a number that represents the similarity) between lists of y coordinates 

#Note: ENSURE that and both lists are of identical length, delta x remains constant and x coordinate is common to both lists

import numpy as np

a = [0, 1, 0.5]
b = [100, 1, 0.5]

output = np.correlate((a - np.mean(a)) / (np.std(a) * len(a)), (b - np.mean(b)) /  np.std(b)) #Normalised correlation

print output