Question

尝试在python中构建搜索功能，从用户获取输入值/字符串，搜索外部文件，然后返回文件中请求值的总计数（总和）。

if user_search_method == 1:
with open("file.txt", 'r') as searchfile:
    for word in searchfile:
        word = word.lower()
        total = 0
        if user_search_value in word.split():
            total += word.count(user_search_value)
            print total

当我运行此操作时，虽然我显示的是逐行计数而不是总和。当我将这些行加起来时，它们总是比实际数量少1个。

Answer 1

您在每次迭代中打印total，您必须将其从for循环中删除。此外，您可以使用一个生成器表达式来完成更多pythonic的工作：

if user_search_method == 1:
    with open("file.txt") as searchfile:
        total = sum(line.lower().split().count(user_search_value) for line in searchfile)
    print total

Answer 2

感觉你的问题可能会遗漏一些东西，但我会尝试让你到达你想去的地方......

user_search_value = 'test'                     # adding this for completeness of 
                                               # this example
if user_search_method == 1:
    with open("file.txt", 'r') as searchfile:
        total = 0
        for word in searchfile:
            words = word.lower().split()       # breaking the words out, upfront, seems
                                               # more efficient

            if user_search_value in words:
                total += words.count(user_search_value)
        print total                            # the print total statement should be outside the for loop

Answer 3

if user_search_method == 1:    
  total = 0    
  with open('file.txt') as f:
    for line in f:
      total += line.casefold().split().count(user_search_value.casefold())
  print(total)

这可能就是你想做的事。

Python：在文件中搜索特定字符串并输出总字符串数

3 个答案: