读取文本文件并将单词作为排序列表返回

Question

For an assignment in Python 3, I need to create a program that will do the following:

1. Open a text file chosen by the user
2. Append all words within text file to a list
3. Sort the words in the list
4. Print the sorted list matching the desired results

The code I have will sort the list but will not dedup the list to the desired results. The text file is the first four lines of a soliloquy from Romeo and Juliet.

fname = input("Enter file name: ")
fh = open(fname)
lst = list()
for line in fh:
    line = line.rstrip()
    words = line.split()
    for word in words:
        lst.append(word)
lst.sort()
print(lst)

The desired result is:

['Arise', 'But', 'It', 'Juliet', 'Who', 'already', 'and', 'breaks', 'east', 'envious', 'fair', 'grief', 'is', 'kill', 'light', 'moon', 'pale', 'sick', 'soft', 'sun', 'the', 'through', 'what', 'window', 'with', 'yonder']

But with my code, I get duplicated words:

['Arise', 'But', 'It', 'Juliet', 'Who', 'already', 'and', 'and', 'and', 'breaks', 'east', 'envious', 'fair', 'grief', 'is', 'is', 'is', 'kill', 'light', 'moon', 'pale', 'sick', 'soft', 'sun', 'sun', 'the', 'the', 'the', 'through', 'what', 'window', 'with', 'yonder']

How can I dedupe the list?

Answer 1

There are a few ways you can do this. You can check if the word is already in the list, and only append when the word is not in the list:

for word in words:
    if word not in lst:
        lst.append(word)
lst.sort()

If the word is already in the list, you don't do anything, so I think that is all you need.

You can also convert your list to a set (sets can only have a single instance of each unique value they contain). The kind of clunky thing about this is that you will then need to convert it back to a list to sort it (sets are unsorted by nature, although there are other libraries that give you sorted options), and to match the required output format (I assume they require a list output):

for word in words:
    lst.append(word)
lst = sorted(set(lst))  # convert to set and sort in one line. Returns a list.

I'd assume the first option seems more illustrative of what you are likely expected to be learning for this assignment.

Answer 2

Instead of list, use set to collect words. At the end, convert to list and sort

fname = input("Enter file name: ")
words = set()
with open(fname) as fh:
    for line in fh:
        line = line.rstrip()
        words.update(set(line.split()))

words_list = sorted(list(words))
print(words_list)

Answer 3

One possibility would be to use a set , maybe like this:

filename = input("Enter file name: ")
words = set()

with open(filename) as f:
    for line in f:
        line = line.strip()
        if len(line) > 0:
            for w in line.split()
                w = w.strip()
                if len(w) > 0:
                    words.add(w)

print(words)
sorted_words = list(sorted(words))
print(sorted_words)