python 去除 list 重复元素

比较容易记忆的是用内置的setl1 = ['b','c','d','b','c','a','a']l2 = list(set(l1))print l2 还有一种据说速度更快的，没测试过两者的速度差别l1 = ['b','c','d','b','c','a','a']l2 = {}.fromkeys(l1).keys()print l2 这两种都有个缺点，祛除重复元素后排序变了：['a', 'c', 'b', 'd']     如果想要保持他们原来的排序： 用list类的sort方法l1 = ['b','c','d','b','c','a','a']l2 = list(set(l1))l2.sort(key=l1.index)print l2也可以这样写l1 = ['b','c','d','b','c','a','a']l2 = sorted(set(l1),key=l1.index)print l2  也可以用遍历l1 = ['b','c','d','b','c','a','a']l2 = []for i in l1:    if not i in l2:        l2.append(i)print l2上面的代码也可以这样写l1 = ['b','c','d','b','c','a','a']l2 = [][l2.append(i) for i in l1 if not i in l2]print l2  这样就可以保证排序不变了：['b', 'c', 'd', 'a']