读/写文本文件 [英] Read/Write text file

问题描述

我正在尝试更改文本文件中的某些行而不影响其他行。这就是文本文件中名为text.txt的内容。

I am trying to change a some lines in a text file without affecting the other lines. This is what's inside the text file called "text.txt"

this is  a test1|number1
this is a test2|number2
this is a test3|number2
this is a test4|number3
this is a test5|number3
this is a test6|number4
this is a test7|number5
this is a test8|number5
this is a test9|number5
this is a test10|number5

我的目标是更改第4行和第5行，但保持其余部分相同。

My objective is to change the line 4 and line 5 but keep the rest same.

mylist1=[]
for lines in open('test','r'):
    a=lines.split('|')
    b=a[1].strip()
    if b== 'number3':
        mylist1.append('{}|{} \n'.format('this is replacement','number7'))
    else:
         mylist1.append('{}|{} \n'.format(a[0],a[1].strip()))
myfile=open('test','w')
myfile.writelines(mylist1)

即使代码有效，我也是想知道是否有任何更好的事情r和有效的方法吗？是否可以通过行号读取文件？

Even though the code works, I am wondering if there is any better and efficient way to do it? Is it possible to read the file just by line number?

推荐答案

你无法改进。但您必须将所有行写入新文件，无论是更改还是未更改。小改进将是：

There is not much you can improve. But you have to write all lines to a new file, either changed or unchanged. Minor improvements would be:

• 使用和语句;


• 避免在列表中存储行;


• 写入行而不在中格式化其他子句（如果适用）。

• using the with statement;
• avoiding storing lines in a list;
• writing lines without formatting in the else clause (if applicable).

应用以上所有内容：

import shutil
with open('test') as old, open('newtest', 'w') as new:
    for line in old:
        if line.rsplit('|', 1)[-1].strip() == 'number3':
            new.write('this is replacement|number7\n')
        else:
            new.write(line)
shutil.move('newtest', 'test')

这篇关于读/写文本文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！