如何使用Python对字数排序？

Question

我使用这个代码来计算文本文件中的相同单词

filename = input("Enter name of input file: ")
file = open(filename, "r", encoding="utf8")
wordCounter = {}
with open(filename,'r',encoding="utf8") as fh:
  for line in fh:
    # Replacing punctuation characters. Making the string to lower.
    # The split will spit the line into a list.
    word_list = line.replace(',','').replace('\'','').replace('.','').replace("'",'').replace('"','').replace('"','').replace('#','').replace('!','').replace('^','').replace('$','').replace('+','').replace('%','').replace('&','').replace('/','').replace('{','').replace('}','').replace('[','').replace(']','').replace('(','').replace(')','').replace('=','').replace('*','').replace('?','').lower().split()
    for word in word_list:
      # Adding  the word into the wordCounter dictionary.
      if word not in wordCounter:
        wordCounter[word] = 1
      else:
        # if the word is already in the dictionary update its count.
        wordCounter[word] = wordCounter[word] + 1

print('{:15}{:3}'.format('Word','Count'))
print('-' * 18)
# printing the words and its occurrence.
for  word,occurance  in wordCounter.items():
  print(word,occurance)

我需要他们以较大的数字到较小的数字作为输出。例如：

字1:25

单词2:12

单词3:5 . . .

我还需要以“.txt”文件的形式获取输入。如果用户写入任何不同的内容，则程序必须得到一个错误，即“写入有效的文件名”

如何对输出进行排序并同时生成错误代码

Answer 1

您可以尝试：

if ( filename[-4:0] != '.txt'):
    print('Please input a valid file name')

并重复输入命令

Answer 2

对于按顺序打印，您可以在打印之前按引用对其进行排序，如下所示：

for  word,occurance  in sorted(wordCounter.items(), key=lambda x: x[1], reverse=True):
  print(word,occurance) 

<>为了检查文件是否以你想要的方式有效，你可以考虑使用：

import os

path1 = "path/to/file1.txt"
path2 = "path/to/file2.png"

if not path1.lower().endswith('.txt'):
    print("Write a valid file name")

if not os.path.exists(path1):
    print("File does not exists!")