remove_duplicate.py

def f7(seq):
    seen = set()
    seen_add = seen.add
    return [x for x in seq if not (x in seen or seen_add(x))]

data = open("data.txt").read().splitlines()
data2 = open("data.txt").read().splitlines()
data = f7(data)

for i in xrange(len(data)-1,-1,-1):
    if data[i] in data2:
        data.remove(data[i])

open("result.txt","wb").write(data)