我想检查一个字符串是否在文本文件中。如果是,执行x。如果不是,执行y。然而,由于某种原因,这段代码总是返回True。有人能看出哪里不对吗?

def check():
    datafile = file('example.txt')
    found = False
    for line in datafile:
        if blabla in line:
            found = True
            break

check()
if True:
    print "true"
else:
    print "false"

当前回答

"found"需要在函数中作为全局变量创建,因为"if else"语句不在函数中。您也不需要使用“break”来中断循环代码。 下面的方法可以确定文本文件是否有所需的字符串。

with open('text_text.txt') as f:
    datafile = f.readlines()


def check():
    global found
    found = False
    for line in datafile:
        if 'the' in line:
            found = True


check()

if found == True:
    print("True")
else:
    print("False")

其他回答

两个问题:

你的函数没有返回任何东西;不显式返回任何内容的函数返回None(这是假的) True始终为True—您不是在检查函数的结果

.

def check(fname, txt):
    with open(fname) as dataf:
        return any(txt in line for line in dataf)

if check('example.txt', 'blabla'):
    print "true"
else:
    print "false"

found = False

def check():
    datafile = file('example.txt')
    for line in datafile:
        if blabla in line:
            found = True
            break
    return found

if check():
    print "true"
else:
    print "false"

如何搜索文件中的文本并返回在其中找到的字的文件路径 (Какискатьчастьтекставфайлеивозвращятьпутькфайлувкоторомэтословонайдено)

import os
import re

class Searcher:
    def __init__(self, path, query):
        self.path   = path

        if self.path[-1] != '/':
            self.path += '/'

        self.path = self.path.replace('/', '\\')
        self.query  = query
        self.searched = {}

    def find(self):
        for root, dirs, files in os.walk( self.path ):
            for file in files:
                if re.match(r'.*?\.txt$', file) is not None:
                    if root[-1] != '\\':
                        root += '\\'           
                    f = open(root + file, 'rt')
                    txt = f.read()
                    f.close()

                    count = len( re.findall( self.query, txt ) )
                    if count > 0:
                        self.searched[root + file] = count

    def getResults(self):
        return self.searched

在Main ()

# -*- coding: UTF-8 -*-

import sys
from search import Searcher

path = 'c:\\temp\\'
search = 'search string'


if __name__ == '__main__':

    if len(sys.argv) == 3:
        # создаем объект поисковика и передаем ему аргументы
        Search = Searcher(sys.argv[1], sys.argv[2])
    else:
        Search = Searcher(path, search)

    # начать поиск
    Search.find()

    # получаем результат
    results = Search.getResults()

    # выводим результат
    print 'Found ', len(results), ' files:'

    for file, count in results.items():
        print 'File: ', file, ' Found entries:' , count

这是另一个。获取绝对文件路径和给定字符串并将其传递给word_find(),在enumerate()方法中对给定文件使用readlines()方法,该方法在逐行遍历时给出可迭代计数,最终为您提供具有匹配字符串的行,加上给定的行号。欢呼。

  def word_find(file, word):
    with open(file, 'r') as target_file:
        for num, line in enumerate(target_file.readlines(), 1):
            if str(word) in line:
                print(f'<Line {num}> {line}')
            else:
                print(f'> {word} not found.')


  if __name__ == '__main__':
      file_to_process = '/path/to/file'
      string_to_find = input()
      word_find(file_to_process, string_to_find)

"found"需要在函数中作为全局变量创建,因为"if else"语句不在函数中。您也不需要使用“break”来中断循环代码。 下面的方法可以确定文本文件是否有所需的字符串。

with open('text_text.txt') as f:
    datafile = f.readlines()


def check():
    global found
    found = False
    for line in datafile:
        if 'the' in line:
            found = True


check()

if found == True:
    print("True")
else:
    print("False")