python - 在 python 2.7 中搜索重复值列表

Question

list1 = ["green","red","yellow","purple","Green","blue","blue"]

所以我得到了一个列表，我想循环遍历列表，看看颜色是否没有被多次提及。如果有，则不会附加到新列表。

所以你应该留下

list2 = ["red","yellow","purple"]

我试过了

list1 = ["green","red","yellow","purple","Green","blue","blue","yellow"]
list2 =[]
num = 0
for i in list1:
    if (list1[num]).lower == (list1[i]).lower:
        num +=1
    else:
        list2.append(i)
        num +=1

但是我总是报错

Answer 1

使用计数器:https://docs.python.org/2/library/collections.html#collections.Counter .

from collections import Counter
list1 = ["green","red","yellow","purple","green","blue","blue","yellow"]
list1_counter = Counter([x.lower() for x in list1])
list2 = [x for x in list1 if list1_counter[x.lower()] == 1]

请注意，您的示例是错误的，因为 yellow 出现了两次。