Spearman's Rank Correlation Coefficient (Unique Data Sets) - Python

spearman_unique.py

def main():
    n = int(raw_input().strip())
    X = map(float, raw_input().strip().split(' '))
    Y = map(float, raw_input().strip().split(' '))
    x_rank = ranking(X)
    y_rank = ranking(Y)
    d_sq = [(x-y)**2 for x,y in zip(x_rank, y_rank)]
    print round(1-((6.0*sum(d_sq))/(n*(n**2 - 1))), 3)
    

def ranking(arr):
     cp = []
     for x in arr:
         if cp.count(x) == 0:
             cp.append(x)     
     cp.sort()
     ranks = {x:y for x,y in zip(cp, range(1, len(cp)+1))}
     return [ranks[x] for x in arr]

main()