如果-multiple-元素不在列表中,那么

Question

我目前正在尝试在许多其他项目的列表中创建一些不需要的项目的黑名单.

我目前有这个非常丑陋的条件语句,它可以正常工作,但我觉得添加它看起来很乏味,而且看起来很糟糕.我必须手动添加它,我发现这是一个问题,因为我想根据我的代码中的函数添加到黑名单,所以手动添加将不再足够.

我希望"NEW"成为所需项目的标题,并且所有条件都是"不在黑名单",这似乎非常重复.

if "NEW" in lst[i][0] and "Pears" not in lst[i][0] and "Strawberries" not in lst[i][0] and "Oranges" not in lst[i][0] and "Cherries" not in lst[i][0] and "Plums" not in lst[i][0] and "Nectarines" not in lst[i][0] and "raspberries" not in lst[i][0] and "Apples" not in lst[i][0]:

我想找到一种方法来简单地创建一个黑名单列表,并且如果在另一个列表中找不到黑名单中的任何项目,则继续python.

我已经尝试创建黑名单列表并尝试:

lst = ['Broccoli', 'Chicken', 'Oranges', 'Apples', 'Squash', ' Salmon']

blacklist = ['Pears', 'Strawberries', 'Oranges']

#My actual lists are much longer

for i in range(len(lst)):
    for blacklisteditem in blacklist:
        if blacklisteditem in lst[i]:
            print("This item is not blacklisted, proceeding..")
        else:
            print("This item was blacklisted")

但这回归:

This item was blacklisted
This item was blacklisted
This item was blacklisted
This item was blacklisted
This item was blacklisted
This item was blacklisted
This item was blacklisted
This item was blacklisted
This item is not blacklisted, proceeding..
This item was blacklisted
This item was blacklisted
This item was blacklisted
This item was blacklisted
This item was blacklisted
This item was blacklisted
This item was blacklisted
This item was blacklisted
This item was blacklisted

显然不是这里的目标.必须有一些我忽视的解决方案,任何人都可以帮助我吗？我只想应用"if x not in lst:"的逻辑,但是我希望x是多个项目,最好是列表中的那些项目,或者我可以附加的字符串？

我基本上需要能够以某种方式附加到此黑名单,而不必手动编辑脚本,因为我希望我的程序能够添加其他条目.如果这涉及到某种方式附加长而丑陋的条件,那就没关系,只要它有效.

Answer 1

将您的黑名单设为一组,并测试您的列表是否没有交集(该组是不相交的):

blacklist = {'Pears', 'Strawberries', 'Oranges'}
if blacklist.isdisjoint(lst):
    print("This item is not blacklisted, proceeding..")
else:
    print("This item was blacklisted")

仅当没有共同的元素时,该set.isdisjoint()方法True才会返回:

>>> lst = ['Broccoli', 'Chicken', 'Oranges', 'Apples', 'Squash', ' Salmon']
>>> blacklist = {'Pears', 'Strawberries', 'Oranges'}
>>> blacklist.isdisjoint(lst)
False
>>> blacklist.isdisjoint(['Broccoli', 'Chicken', 'Apples', 'Squash', ' Salmon'])
True

您的尝试不会等到所有列入黑名单的物品都经过测试; 为所测试的每个元素打印.你需要等到你的for循环完成,然后得出没有blacklist出现任何元素的结论.