source = ["a "," 1 "," b "," 1 "," c "," 2 "," d "," 3 "," e "," 4 "," c "," 3"]
out = []
對於zip中的e(source[0::2],source[1::2]):
....如果e[1]不是in out:
........out = out + list(e)
打印(輸出)