将\\ r \\ n转换为文本区域中的换行符（不使用 <br> 标签）

Question

I have searched throughout this site and google, and could not find a viable solution. There are solutions, but none seem to work for me.

I have a text area that serves as the input for a form, as well as the output (editable) when displaying the form to edit. So, I have a textarea like so:

echo '<textarea>'.$resolution.'</textarea>';

If I enter something with line breaks, it is interpreted as \\r\\n wherever there is a carriage return. Example:

Input: 
    This is a

    test.

Output:
    This is a\\r\\n\\r\\ntest.

Now, I found it simple to remove the extra slash by using stripslashes as follows:

$resolution = stripslashes($resolution);

...but, now the output is:

This is a\r\n\r\ntest.

I cannot figure out how to convert \\r\\n to a line break (that is, without using a
tag, since that would only output <br> within the textarea, where html would not be supported. I've tried all of the following, but none of them worked:

//Effort 1
$resolution = trim($resolution);

//Effort 2
$resolution = nl2br($resolution);

//Effort 3
$resolution = htmlentities($resolution);

//Effort 4
$resolution = preg_replace("\\r\\n","<br>",$resolution);

I'm now at a complete loss. Can anyone shed some light on this?

Answer 1

Just use double quotes on str_replace

str_replace('\r',"\r",str_replace('\n',"\n",$resolution));

http://php.net/manual/en/language.types.string.php

or if you're really dealing with double backslashes:

str_replace('\\\\r',"\r",str_replace('\\\\n',"\n",$resolution));

Answer 2

PHP has two different string building modes. The first uses single quotes, and will do absolutely no variable or special character substitutions. That's what you're using.

The second is variable-embedding in double quoted strings, which should work:

$text = str_replace("\\", "\", $text);
echo "<textarea>$text</textarea>";

The \\r and \\n should now be active carriage return and newline characters in your output, not the character "slash" and then an 'r' or 'n'