r +和w +模式之间的确切区别是什么? [英] What is the exact difference between r+ and w+ modes?

问题描述

我试图使用它们两个打开文件，但结果相同.

I tried to use both of them opening a file but got the same result.

w + 不存在，而 r + 不存在，则应该创建一个新文件.这是唯一的区别吗?

w+ is supposed to create a new file if it doesn't exist while r+ not. Is this the only difference?

例如，这是一个初始文件 file.txt

For example, this is an initial file file.txt

Line 1
Line 2
Line 3

1)实施 r + 模式(写出"hello"一词)后， file.txt /p>

1) file.txt after implementing of r+ mode (writing the word "hello")

hello

2)实施 w + 模式后， file.txt >

2) file.txt after implementing of w+ mode

hello

我猜想 r + 会将输入追加到文件的开头.

I guessed that r+ would append an input to the beginning of the file.

因此，第一个区别是关于创建一个不存在的文件，第二个区别是r +在w +被截断的同时会被覆盖，对吗?(而不是出现了一个问题，即覆盖和截断是否是相同的概念)

EDITED: So, the 1st difference is about creating a file that doesn't exist and the 2nd difference is that r+ overwrites while w+ truncates, right? (than the question arises whether overwriting and truncating are the same concepts or not)

推荐答案

先删除 file.txt ，您将了解其中的区别.

Remove file.txt first and you'll understand the difference.

w + 将创建文件.

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