我需要在文件中只使用find（）命令编写一个Python程序来打印所有那些拥有Python的行 [英] I need to write a Python program using only find() command in files to print all those line which has Python

问题描述

我需要在文件中使用find（）命令打印出现python的所有行。使用python。

I need do to print all that lines in which python appears using find() command in a file. Using python.

fhand=open('demo.txt')                           
for line in fhand:
        line=line.rstrip()
        if(line.find('python')):
           continue
        print(line)

这些是我的文件内容

these are my file content

python is fun
python java 
sai python
sachin
ganesha

目前仅打印前2行



我尝试了什么：

currently its printing first 2 lines only

What I have tried:

fhand=open('demo.txt')
for line in fhand:
        line=line.rstrip()
        if(line.find('python')):
           continue
        print(line)

这是我的代码，请帮帮我

this is my code please help me

推荐答案

fhand=open('demo.txt')
for line in fhand:
  line=line.rstrip()
  if( line.find('python') != -1):
    print(line)

find 方法将索引返回到第一次出现的查找目标。您只打印索引为零的那些。将您的循环更改为：

The find method returns the index to the first occurrence of the find target. You are only printing the ones where the index is zero. Change your loop to:

for line in fhand:
  line=line.rstrip()
  if(line.find('python') != -1):
    print(line)

将来请在< pre lang =之间正确格式化代码蟒>< /预>标签，正如我在这里所做的那样。它使它更具可读性。

In future please format your code properly between <pre lang="Python"></pre> tags, as I have done here. It makes it more readable.

if(line.find('python')):
  continue

Python String find（）方法 [ ^ ]

根据文档 find（）为'找不到'返回-1，为'找到'返回索引（0）...但是'if'是关于ture / false，其中除0以外的任何数字是真的......

Python String find() Method[^]
According to the documentation find() returns -1 for 'not-found' and index (0 based) for 'found'... However 'if' is about ture/false, where any number except 0 is true...

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