如何获取文本中出现的所有单词

【问题】

I have this csv file

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

I want to make all the words start with a small letter and create a list which will include all the unique items from the above csv file. Have you any idea? Thanks in advance! So far, I have managed to convert all the words with a small letter:

unique_row_items = set([field.strip().lower()for field in row])

But i can't manage the other one.

def unique():

    rows = list(csv.reader(open('example_1.csv', 'r'), delimiter=','))

    result = []

    for r in rows:

        key = r

        if key not in result:

            result.append(r)

    return result

Which does not give the results I want

【回答】

这个问题用SPL实现很方便，脚本如下：

	A
1	= file("D://Words.txt").read()
2	=lower(A1)
3	=A2.words().id()

A1：从文本读取字符串

A2：将字符串转换成小写字母

A3：通过 words 函数将字符串拆分成单个单词组成的序列，再通过 id 函数去除重复成员