在 PHP 的 str_replace() 中，双反斜杠是什么意思? [英] In PHP's str_replace(), what does the double backslash mean?

问题描述

我想删除所有 \r \n \r\n 这很容易，所以我写道:

I want to remove all \r \n \r\n which is pretty easy to so I wrote:

str_replace(array("\r","\n"),"",$text);

但我看到了这一行:

str_replace(array("\r","\n","\\r","\\n"),"",$text);

我想知道双反斜杠是什么意思\\r 和\\n.

and I was wondering what is the double backslash means \\r and \\n.

推荐答案

\ 是一个转义符，用于对后面的字符进行转义.

\ is an escape character, it's used to escape the following character.

在"\n"中，反斜杠转义n，结果将是一个换行字符.

In "\n", the backslash escapes n and the result will be a new line character.

在"\\n"中，第一个反斜杠转义第二个反斜杠，n保持原样，所以结果是一个包含<的字符串代码>\n(字面意思).

In "\\n", the first backslash escapes the second backslash and the n is kept as is, so the result is a string containing \n (literally).

参见PHP官方文档>字符串.

在您的问题的上下文中，str_replace() 将删除新行("\n" 和 "\r")和还要从字符串中删除 \n 和 \r ("\\n" and "\\r"分别).文本没有理由包含单词 \n 和 \r，所以似乎使用 "\\n" 和 "\\r" 对这里没有兴趣.

In the context of your question, str_replace() will remove new lines ("\n" and "\r") and also remove \n and \r from the string ("\\n" and "\\r" respectively). There's no reason a text contains the words \n and \r, so it seems that using "\\n" and "\\r" has no interest here.

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