How to Match \\r and \\n in PHP Without Using [\\r\\n]?

Matching r and n Without [rn] in PHP

In PHP, the challenge of matching r and n without using [rn] requires a different approach.

PCRE and Newlines

PCRE provides several escape sequences for handling newlines, including R.

• R with Default Settings: Matches Unicode newlines but can be configured using modifiers.
• R with u (Unicode) Modifier: Matches any Unicode newline sequence.
• R with (*BSR_ANYCRLF) Modifier: Restricts R to match CR, LF, or CRLF only.

Example:

<code class="php">$string = "
Test
";

// Match any Unicode newline sequence
if (preg_match('~\R~u', $string)) {
  echo "Matched CR, LF, or any Unicode newline.";
}</code>

Additional Options for Newline Conventions

PCRE supports five conventions for indicating line breaks in strings:

• (*CR) - Carriage return
• (*LF) - Linefeed
• (*CRLF) - Carriage return, followed by linefeed
• (*ANYCRLF) - Any of the three above
• (*ANY) - All Unicode newline sequences

Using (*ANYCRLF) ensures that only CR, LF, or CRLF is matched.

<code class="php">if (preg_match('~(*ANYCRLF)\R~', $string)) {
  echo "Matched CR, LF, or CRLF.";
}</code>

Note

Within character classes, R loses its special meaning and is treated as the literal "R" character.

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