我如何在 python 中读取、附加和排序文本文件的所有单词？

Question

Open the file romeo.txt and read it line by line. For each line, split the line into a list of words using the split() function. The program should build a list of words. For each word on each line check to see if the word is already in the list and if not append it to the list. When the program completes, sort and print the resulting words in alphabetical order.

http://www.pythonlearn.com/code/romeo.txt

Here's my code :

fname = raw_input("Enter file name: ")
fh = open(fname)
for line in fh:
     for word in line.split():
          if word in line.split():
               line.split().append(word)
          if word not in line.split():
               continue
          print word

It only returns the last word of the last line, for some reason.

Answer 1

At the top of your loop, add a list to which you'll collect your words. Right now you are just discarding everything.

Your logic is also reverse, you are discarding words that you should be saving.

words = []
fname = raw_input("Enter file name: ")
fh = open(fname)
for line in fh:
     for word in line.split():
          if word not in words:
               words.append(word)
fh.close()

# Now you should sort the words list and continue with your assignment

Answer 2

Try the following, it uses a set() to build a unique list of words. Each word is also lower-cased so that "The" and "the" are treated the same.

import re

word_set = set()
re_nonalpha = re.compile('[^a-zA-Z ]+')

fname = raw_input("Enter file name: ")

with open(fname, "r") as f_input:
    for line in f_input:
        line = re_nonalpha.sub(' ', line)  # Convert all non a-z to spaces

        for word in line.split():
            word_set.add(word.lower())

word_list = list(word_set)
word_list.sort()
print word_list

This will display the following list:

['already', 'and', 'arise', 'bits', 'breaks', 'but', 'east', 'envious', 'fair', 'grief', 'has', 'is', 'it', 'juliet', 'kill', 'light', 'many', 'moon', 'pale', 'punctation', 'sick', 'soft', 'sun', 'the', 'this', 'through', 'too', 'way', 'what', 'who', 'window', 'with', 'yonder']

Answer 3

sorted(set([w for l in open(fname) for w in l.split()])) 

Answer 4

I think you misunderstand what line.split() is doing. line.split() will return a list containing the "words" that are in the string line . Here we interpret a "word" as "substring delimited by the space character". So if line was equal to "Hello, World. I <3 Python" , line.split() would return the list ["Hello,", "World.", "I", "<3", "Python"] .

When you write for word in line.split() you are iterating through each element of that list. So the condition word in line.split() will always be true! What you really want is a cumulative list of "words you have already come across". At the top of the program you would create it using DiscoveredWords = [] . Then for every word in every line you would check

if word not in DiscoveredWords:
    DiscoveredWords.append(word)

Got it? :) Now since it seems you are new to Python (welcome to the fun by the way) here is how I would have written the code:

fname = raw_input("Enter file name: ")
with open(fname) as fh:
    words = [word for line in fh for word in line.strip().split()]
words = list(set(words))
words.sort()

Let's do a quick overview of this code so that you can understand what is going on:

with open(fname) as fh is a handy trick to remember. It allows you to ensure that your file gets closed! Once python exits the with block it will close the file for you automatically :D

words = [word for line in fh for word in line.strip().split()] is another handy trick. This is one of the more concise ways to get a list containing all of the words in a file! We are telling python to make a list by taking every line in the file ( for line in fh ) and then every word in that line ( for word in line.strip().split() ).

words = list(set(words)) casts our list to a set and then back to a list . This is a quick way to remove duplicates as a set in python contains unique elements.

Finally we sort the list using words.sort() .

Hope this was helpful and instructive :)

Answer 5

words=list()
fname = input("Enter file name: ")
fh = open(fname).read()
fh=fh.split()

for word in fh:
    if word in words:
        continue
    else:
        words.append(word)
words.sort()
print(words)