python - 如何检查列表的元素是否在字符串中

Question

这个问题的反面（在列表中查找字符串）非常受欢迎，以至于我无法找到我的问题的答案。

black_list = ["ab:", "cd:", "ef:", "gh:"]

for line in some_file:
    if ":" in line and black_list not in line:
        pass

这显然是行不通的。需要对列表进行一些迭代以返回真/假，但我不知道如何优雅地完成它。谢谢。

Answer 1

内置any()函数可以在这里为您提供帮助：

black_list = ["ab:", "cd:", "ef:", "gh:"]

for line in some_file:
    if ":" in line and not any(x in line for x in black_list):
        pass

也可以通过以下方式获得相同的效果all()：

for line in some_file:
    if ":" in line and all(x not in line for x in black_list):
        pass

...但我认为第一个更接近英语，所以更容易理解。

Answer 2

您的示例代码看起来像是在文件中查找元素，而不仅仅是在字符串中。无论如何，你可以做这样的事情，这说明了用内置any()函数做这两个：

def check_string(text, word_list):
    return any(phrase in text for phrase in word_list)

def check_file(filename, word_list):
    with open(filename) as some_file:
        return any(check_string(line, word_list) for line in some_file)

black_list = ["ab:", "cd:", "ef:", "gh:"]

print check_file('some_file.txt', black_list)

Answer 3

您可以检查 black_list 中的每个“标志”，并过滤包含 black_list 的行。这可以使用all()：

for line in some_file:
    filtered = all(i in line for i in black_list)
    if filtered and ':' in line:
        # this line is black listed -> do something
    else:
        # this line is good -> do something

以上检查是否存在 black_list 的所有元素。使用any(), 如果您想在 black_list 的任何元素存在时拒绝一行：

for line in some_file:
    filetered = any(i in line for i in black_list_2)
    if filtered:
        # this line contains at least one element of the black_list
    else:
        # this line is fine