我有这个csv文件
Cat, and, dog, bites
Yahoo, news, claims, a, cat, mated, with, a, dog, and, produced, viable, offspring
Cat, killer, likely, is, a, big, dog
Professional, free, advice, on, dog, training, puppy, training
Cat, and, kitten, training, and, behavior
Dog, &, Cat, provides, dog, training, in Eugene, Oregon
Dog, and, cat, is, a, slang, term, used, by, police, officers, for, a, male-female, relationship
Shop, for, your, show, dog, grooming, and, pet, supplies
我想使所有单词都以小写字母开头，并创建一个列表，其中将包含上述csv文件中的所有唯一项。你有什么主意吗 提前致谢！到目前为止，我已经设法将所有单词转换为一个小字母：
unique_row_items = set([field.strip().lower() for field in …